Compositions and methods for the detection and analysis of mycobacterium tuberculosis

ABSTRACT

Provided herein are compositions and methods useful for the detection of MTB. In particular, provided herein are kits, reagents, reaction mixtures, and methods involving such for nucleic acid amplification and detection procedures, which specifically and sensitively detect MTB in samples.

FIELD OF THE INVENTION

The present invention relates to mycobacterium tuberculosis. Inparticular, the invention relates to compositions and method fordetecting mycobacterium tuberculosis.

BACKGROUND OF THE INVENTION

Mycobacterium tuberculosis (MTB) constitutes a serious threat to publichealth in the world and is second only to HIV/AIDS as the greatestkiller worldwide due to a single infectious agent (Warren et al,Differentiation of Mycobacterium tuberculosis complex by PCRamplification of genomic regions of difference, 2006 July, Int J TubercLung Dis. 10 (7):818-822). The CDC reports that in 2011, there were anestimated 8.7 million new cases of MTB (13% co-infected with HIV); 1.4million people died from MTB, including almost one million deaths amongHIV-negative individuals and 430,000 among people who were HIV-positive.The World Health Organization (WHO) reports that MTB is one of the topkillers of women, with 300,000 deaths among HIV-negative women and200,000 deaths among HIV-positive women in 2011. It is among the topthree causes of death for women aged 15 to 44. MTB is also a leadingkiller of people living with HIV causing one quarter of all deaths.There were an estimated 0.5 million cases and 64,000 deaths amongchildren in 2011. Multi-drug resistant MTB (MDR-TB) is increasing and ispresent in virtually all countries surveyed. Geographically, the burdenof MTB is highest in Asia and Africa. WHO reported that overall MTB casedetection is still less than 60% in low-income countries (LICs) and only66% globally. That is, of an estimated 8.7 million people who become illwith MTB in 2011, 2.9 million with active disease were not diagnosed andnotified to national MTB control programs. In addition, only 19% ofMDR-MTB cases were appropriately diagnosed and notified. Fewer than 1 in20 new MTB patients have access to drug susceptibility testing. Due tothe risk of spread of MTB, the potential for the emergence ofdrug-resistant strains, and the severity of the disease in patientsinfected with HIV-1, a low price, prompt and accurate MTB molecular testis extremely important. Routine cultures are time-consuming and can takeup to six weeks. Microscopic examination of acid-fast smears is the mostrapid method for the detection of mycobacteria, but it is insensitiveand non-specific.

SUMMARY OF THE INVENTION

Provided herein are compositions and methods useful for the detection ofMTB. In particular, provided herein are kits, reagents, reactionmixtures, and methods involving such for nucleic acid amplification anddetection procedures, which specifically and sensitively detect MTB insamples. Such compositions and method include primers, probes, primersets, primer and probe sets, and methods for detecting MTB complex indifferent human samples such as sputum, bronchial alveolar lavage (BAL)and N-acetyl-L-cysteine (NALC)-NaOH sediments of sputum and BAL samples.

In some embodiments, two or more of the polynucleotide reagents providedherein as SEQ ID NOs: 1-9 are combined in a composition (e.g., reagentset, kit, reaction mixture, etc.). In some embodiments, one or more orall of the nucleic acid reagents comprise a detectable moiety (e.g.,synthetic label). In some embodiments, the compositions comprise one ormore primers SEQ ID NOs: 1-4 or 7-8. In some embodiments, thecompositions comprise one or more primer pairs SEQ ID NOs: 1 and 2, 3and 4, or 7 and 8. In some embodiments, the compositions comprise one ormore probes (e.g., labeled probes) of SEQ ID NOs: 5, 6, or 9. In someembodiments, the compositions comprise primer and probe sets: SEQ ID NOs1-2 and 5, 3-4 and 6, or 7-9. In some embodiments, the compositionscomprise internal control reagents, such as SEQ ID NOs: 7-9. In someembodiments, the compositions comprise a dual probe system comprisingSEQ ID NOs: 5 and 6.

In some embodiments, the compositions and methods employ reagents setscomprising a polynucleotide component having primers, probes, primerssets, and/or probe sets. In some embodiments, the polynucleotidecomponent of the composition consists of the primer, probe, primer set,or probe set combinations described above. As reaction mixtures, thecompositions may consist of such polynucleotides as well as anypolynucleotides included in a sample (i.e., the only non-sample nucleicacid molecules are the polynucleotides represented by SEQ ID NOs: 1-9,individually or in combinations (e.g., the combinations describedabove).

The primer sets herein provided comprise two primers, and are useful forthe amplification of target sequences, e.g., in PCR. In someembodiments, the compositions comprise at least two primers and one ormore (e.g., two or more) probes that detect amplicons generated by theprimers.

Also provided herein are methods for detecting MTB in a sample. In someembodiments, the methods comprise (a) forming a reaction mixturecomprising nucleic acid amplification reagents, at least polynucleotideprimer or probe described herein, and a test sample potentiallycontaining at least one target sequence; and (b) subjecting the mixtureto amplification conditions to generate at least one copy of a nucleicacid sequence complementary to the target sequence. In some embodimentsthe method further comprises detecting generated amplicons. In someembodiments, the detecting comprises (c) hybridizing a probe to thenucleic acid sequence complementary to the target sequence so as to forma hybrid comprising the probe and the nucleic acid sequencecomplementary to the target sequence; and (d) detecting, directly orindirectly, the hybrid as an indication of the presence of MTB in thetest sample.

Further, when the amplification is PCR, or a similar thermocyclingamplification process, step (b) can be repeated multiple times toincrease the number of target sequence copies.

According to another embodiment, both MTB and one or more additionalinfectious agents (e.g., HIV) or other nucleic acid molecules (e.g.,human sequences) are detected. Accordingly, in some embodiments,compositions comprise reagents for detecting such other agents ornucleic acid molecules.

In some embodiments, the compositions and methods further employ controlreagents or kit components (e.g., positive controls, negative controls).In some embodiments, the control reagents include a synthetic targetnucleic acid. In some embodiments, the control reagents include reagentsfor detecting an MTB, human, or other sequence expected to be present ina sample. In some embodiments, a control target nucleic acid, whethersynthetic or endogenous in a sample, is selected such that amplificationprimers that amplify the MTB target nucleic acid also amplify thecontrol target nucleic acid. In some such embodiments, a probe thatdetects the MTB target nucleic acid or an amplicon generated therefromdoes not detect the control target or an amplicon generated therefrom.In some embodiments, a control probe is provided that detects thecontrol target nucleic acid or an amplicon generated therefrom but doesnot detect the MTB target nucleic acid or an amplicon generatedtherefrom. In some embodiments, internal standards are provided forquantitation.

In some embodiments, kits, in addition to the reagents discussed above,include one or more suitable containers, instructions for use, software(e.g., data analysis software), and the like. In some embodiments, kitsinclude reagents for labeling polynucleotides. In some embodiments, oneor more components in the kit is in lyophilized form.

Embodiments of the present disclosure provide compositions, kits,systems, and methods for identifying MTB in complex biological samplessuch as sputum or bronchoalveolar lavage and sediments thereof. In someembodiments, the compositions and methods provide inactivation reagents,and single probe or multiple probe real time detection methods that areable to specifically and accurately isolate and identify MTB.

For example, in some embodiments, the present disclosure provides acomposition, comprising: at least one (e.g., one, two, or three) primerpair(s) selected from SEQ ID NOs: 1 and 2, SEQ ID NOs: 3 and 4, or SEQID NOs: 7 and 8. In some embodiments, the composition comprises SEQ IDNOs: 1-4 and 7-8. In some embodiments, the composition further comprisesat least one probe selected from SEQ ID NOs: 5, 6, or 9.

Further embodiments provide a composition, comprising: a set of primerpairs of SEQ ID NOs: 1 and 2 and SEQ ID NOs: 3 and 4. In someembodiments, the composition further comprises at least one probeselected from SEQ ID NOs: 5, 6, or 9. In some embodiments, thecomposition further comprises the primer pair of SEQ ID NOs: 7 and 8.

Additional embodiments provide a composition, comprising each thenucleic acids of SEQ ID NOs: 1-9. In some embodiments, the abovecompositions include or are substituted with one or more nucleic acidsequences selected from the SEQ ID NOs: 10-36.

Embodiments of the disclosure provide a kit, comprising: a) any of theaforementioned compositions, and b) at least one reagent for performinga nucleic acid amplification reaction (e.g., a nucleic acid polymerase;a plurality of dNTPS, a buffer, or an inactivation reagent). In someembodiments, the inactivation reagent comprises water, a detergent, analcohol, and NaOH (e.g., isopropanol, sodium hydroxide, TWEEN-20, andwater).

In other embodiments, the disclosure provides a reaction mixture,comprising: any of the aforementioned compositions or nucleic acidshybridized to a microbacterium tuberculosis (MTB) nucleic acid. In someembodiments, the MTB target nucleic acid is one or more (e.g., both) ofinsertion sequence (IS) 6110 and Protein Antigen B (PAB).

In further embodiments, the present disclosure provides a method ofidentifying an MTB nucleic acid in a biological sample, comprising: a)contacting a biological sample from a subject with any of theaforementioned nucleic acid primers or probes, and b) directly orindirectly detecting the binding of the nucleic acid primers or probesto the MTB nucleic acid. In some embodiments, the method furthercomprises the step of c) determining the presence of MTB in the samplewhen the binding is detected. In some embodiments, the detecting is viareal time PCR detecting. In some embodiments, the method furthercomprises the step of inactivating MTB in the sample using theinactivation buffer. In some embodiments, the sample is sputum,bronchoalveolar lavage [BAL], or N-acetyl-L-cysteine [NALC] sediments ofsputum and BAL. In some embodiments, the method further comprises thestep of extracting DNA from the sample following inactivation.

Yet other embodiments provide a method of detecting an MTB nucleic acidin a biological sample, comprising: a) inactivating the biologicalsample with an inactivating reagent to generate an inactivated sample;b) extracting DNA from the inactivated sample; c) contacting the DNAwith one or more primer pairs and one or more nucleic acid probes; d)performing an amplification assay to amplify one or more MTB nucleicacid targets; and e) identifying the presence of the targets in thesample.

Further embodiments provide a method of detecting an MTB nucleic acid ina biological sample, comprising: a) inactivating said biological samplewith an inactivating reagent comprising isopropanol, sodium hydroxide,TWEEN-20, and water to generate an inactivated sample; b) extracting DNAfrom the inactivated sample; c) contacting the DNA with one or moreprimer pairs selected from SEQ ID NOs: 1 and 2 and SEQ ID NOs: 3 and 4;and one or more nucleic acid probes selected from SEQ ID NOs: 5 and 6;d) performing an amplification assay to amplify one or more MTB nucleicacid targets; and e) identifying the presence of the targets in saidsample.

Additional embodiments provide a method of detecting an MTB nucleic acidin a biological sample, comprising: a) inactivating said biologicalsample with an inactivating reagent to generate an inactivated sample;b) extracting DNA from the inactivated sample; c) contacting the DNAwith one or more primer pairs selected from SEQ ID NOs: 1 and 2 and SEQID NOs: 3 and 4; and one or more nucleic acid probes selected from SEQID NOs: 5 and 6; d) performing an amplification assay to amplify one ormore MTB nucleic acid targets; and e) identifying the presence of thetargets in the sample.

Other embodiments provide a method of detecting an MTB nucleic acid in abiological sample, comprising: a) inactivating the biological samplewith an inactivating reagent to generate an inactivated sample; b)extracting DNA from the inactivated sample; c) contacting the DNA withone or more primer pairs selected from SEQ ID NOs: 1 and 2 and SEQ IDNOs: 3 and 4; and one or more nucleic acid probes selected from SEQ IDNOs: 5 and 6; d) performing a real time PCR assay to amplify one or moreMTB nucleic acid targets; and e) identifying the presence of the targetsin the sample.

Still other embodiments provide a method of detecting an MTB nucleicacid in a biological sample, comprising: a) inactivating the biologicalsample with an inactivating reagent to generate an inactivated sample;b) extracting DNA from the inactivated sample; c) contacting said DNAwith one or more primer pairs selected from SEQ ID NOs: 1 and 2 and SEQID NOs: 3 and 4; and one or more nucleic acid probes selected from SEQID NOs: 5 and 6; d) performing an amplification assay to amplify one ormore MTB nucleic acid targets selected from IS6110 and PAB; and e)identifying the presence of the targets in the sample.

In certain embodiments, the present disclosure provides a method ofdetecting an MTB nucleic acid in a biological sample, comprising: a)inactivating the biological sample with an inactivating reagent togenerate an inactivated sample; b) extracting DNA from the inactivatedsample; c) contacting the DNA with the primer pairs of SEQ ID NOs: 1 and2 and SEQ ID NOs: 3 and 4; and the nucleic acid probes of SEQ ID NOs: 5and 6; d) performing an amplification assay to amplify one or more MTBnucleic acid targets; and e) identifying the presence of the targets inthe sample.

In some embodiments, the present disclosure provides a method ofdetecting an MTB nucleic acid in a biological sample, comprising: a)inactivating the biological sample with an inactivating reagentcomprising isopropanol, sodium hydroxide, TWEEN-20, and water togenerate an inactivated sample; b) extracting DNA from the inactivatedsample; c) contacting the DNA with the primer pairs of SEQ ID NOs: 1 and2 and SEQ ID NOs: 3 and 4; and the nucleic acid probes of SEQ ID NOs: 5and 6; d) performing an amplification assay to amplify one or more MTBnucleic acid targets; and e) identifying the presence of the targets inthe sample.

Additional embodiments are described herein.

DESCRIPTION OF FIGURES

FIG. 1 shows an MTB assay work-flow diagram in some embodiments of thetechnology provided herein.

FIG. 2 shows data from detection of 46 MTB phylogenetically andgeographically diverse MTB isolates.

FIG. 3 shows an MTB assay work-flow diagram for sample preparation.

FIG. 4 shows mean cycle number values determined when MTB complexgenomic DNAs were tested to determine assay inclusivity.

DETAILED DESCRIPTION

Provided herein are compositions and methods useful for the detection ofMTB. In particular, provided herein are kits, reagents, reactionmixtures, and methods involving such for nucleic acid amplification anddetection procedures, which specifically and sensitively detect MTB insamples.

In some embodiments, provided herein are polynucleotides thatspecifically hybridize with a nucleic acid sequence, or complementthereof, of MTB. These polynucleotides find use to amplify MTB, ifpresent in a sample, and to specifically detect the presence of MTB.Exemplary polynucleotides are described, for example, by SEQ ID NOs: 1-9or 10-36.

In some embodiments, assays described herein utilize multiple (e.g.,two) different MTB-specific primer/probe sets. For example, in someembodiments, a first set is designed to detect the multi-copy insertionelement, IS6110 (Thierry D, et al., Nucleic Acids Res 1990; 18:188), andsecond set, the single copy gene, PAB (Anderson A B, Hansen E B, InfectImmun 1989; 57:2481-2488). Because there have been reports of MTBstrains that lack IS6110 (Mathema B, et al., Clinical MicrobiologyReviews 2006; 19:658-685), or that have a deletion in the PAB gene(Gilpin C M, et al., J Clin Microbiol 2002; 40:2305-2307), the use ofboth targets minimizes the risk of false negative results. Experimentsdescribed herein demonstrated that the dual target strategy results inthe detection of MTB genomic DNA with high reliability.

The mycobacterial cell wall is resistant to conventional cell lysistechniques due to the complex structure of lipophilic molecules andpolysaccharides. Thus, in some embodiments, MTB detection assays utilizea guanidinium thiocyanate-magnetic microparticle purification methodwith optimized incubation temperatures and mixing conditions for TB celllyses and genomic DNA release. Experiments conducted during thedevelopment of embodiments of the assays described herein showed thatthe sample DNA extraction method is comparable in efficiency tomechanical bead beating for TB cell lyses.

Further experiments demonstrated that all 66 MTB complex DNAs (includingeight different MTB complex species) were detected by the assay.Reliability of the assay was assessed in four ways. First, specificityof the assay was assessed by testing 80 potentially differentcross-reactors. None of the potential cross-reactors were detected.Second, a carryover assessment was performed in which high positive MTBsamples were processed alongside negative samples to determine if falsepositives, or carryover, were detected in the negative samples. No falsepositives were observed. Third, various potentially interferingsubstances were tested for their impact on assay performance. Nointerference was observed, except with 8.3% and 5.0% bovine mucus, whereinterference was observed. This interference was removed when the mucusconcentration was reduced to ≦2.5%. When clinical specimens were tested,the rate of specimens with invalid IC results was 0.3%, demonstratingthat the sample preparation methods described herein removed PCRinhibitors in an effective manner. This provides evidence of therobustness of the protocol and indicates that the impact of interferencecaused by bovine mucus is likely not significant to the assay. Finally,a reproducibility study was performed in which multiple users usedmultiple m2000 instrument systems, or manual sample preparation, to testlow positive (three times LOD) and negative panels. 100% reproducibilitywas observed. These data support the robust nature of the assay whenused in analytical studies and clinical samples testing

The clinical utility of the MTB detection assays was assessed by testingsputum and NALC specimens collected from patients suspected of having TBin five countries using both archived samples and prospectivelycollected samples. Overall assay sensitivity was 93%, while it was 99%in smear positive culture positive samples and 81% in smear negativeculture positive samples. Specificity was 97%. The results of theanalytical specificity test and the sputum sample testing from non-TBsuspect population from within the U.S. all showed 100% specificity. Theclinical specificity was determined based on comparison of assay resultswith culture results.

Embodiments of the technology described herein provide high throughput,automated MTB detection with high sensitivity and specificity. Comparedwith conventional culture assays, the technology significantly improvesthe rapid diagnosis of TB by allowing the direct detection ofmycobacteria in clinical specimens. The assays provide superiorsensitivity and specificity compared to conventional acid-fast smearsmicroscopic examination. A gap with current MTB diagnostic assays is thelack of sensitivity in culture positive and smear negative populations(with low TB concentration in samples). Embodiments of the technologyprovided herein fill that gap. Assays provided herein are robust withvery low inhibition rate even if difficult to work with sputum samples.This reduces the time required for repeat testing of invalid samples. Insome embodiments, a multi-copy MTB target is interrogated, providinggreater target sensitivity and less chance of false negative assayresults caused by mutations/deletions in the target region. Embodimentsfurther provide unique and effective MTB inactivation methods.

The term “specifically hybridize” as used herein refers to the abilityof a nucleic acid to bind detectably and specifically to a secondnucleic acid. Polynucleotides specifically hybridize with target nucleicacid strands under hybridization and wash conditions that minimizeappreciable amounts of detectable binding to non-specific nucleic acids.Stringent conditions that can be used to achieve specific hybridizationare known in the art.

A “target sequence” or “target nucleic acid sequence” as used hereinmeans a nucleic acid sequence of MTB or other sequence to be detected(e.g., HIV), or complement thereof, that is amplified, detected, or bothamplified and detected using one or more of the polynucleotides hereinprovided. Additionally, while the term target sequence sometimes refersto a double stranded nucleic acid sequence, those skilled in the artwill recognize that the target sequence can also be single stranded. Incases where the target is double stranded, polynucleotide primersequences preferably amplify both strands of the target sequence. Atarget sequence may be selected that is more or less specific for aparticular organism. For example, the target sequence may be specific toan entire genus, to more than one genus, to a species or subspecies,serogroup, auxotype, serotype, strain, isolate or other subset oforganisms.

The term “test sample” as used herein, means a sample taken from anorganism, biological fluid, environmental sample, or other sample thatis suspected of containing or potentially contains an MTB targetsequence. The test sample can be taken from any biological source, suchas for example, tissue, blood, saliva, sputa, N-acetyl-L-cysteine(NALC)-NaOH sediments of sputum, mucus, bronchial alveolar lavage (BAL),sweat, urine, urethral swabs, cervical swabs, urogenital or anal swabs,conjunctival swabs, ocular lens fluid, cerebral spinal fluid, milk,ascites fluid, synovial fluid, peritoneal fluid, amniotic fluid,fermentation broths, cell cultures, chemical reaction mixtures and thelike. The test sample can be used (i) directly as obtained from thesource or (ii) following a pre-treatment to modify the character of thesample. Thus, the test sample can be pre-treated prior to use by, forexample, preparing plasma or serum from blood, disrupting cells or viralparticles, preparing liquids from solid materials, diluting viscousfluids, filtering liquids, distilling liquids, concentrating liquids,inactivating interfering components, adding reagents, purifying nucleicacids, and the like.

The term “label” as used herein means a molecule or moiety having aproperty or characteristic which is capable of detection and,optionally, of quantitation. A label can be directly detectable, aswith, for example (and without limitation), radioisotopes, fluorophores,chemiluminophores, enzymes, colloidal particles, fluorescentmicroparticles and the like; or a label may be indirectly detectable, aswith, for example, specific binding members. It will be understood thatdirectly detectable labels may require additional components such as,for example, substrates, triggering reagents, quenching moieties, light,and the like to enable detection and/or quantitation of the label. Whenindirectly detectable labels are used, they are typically used incombination with a “conjugate”. A conjugate is typically a specificbinding member that has been attached or coupled to a directlydetectable label. Coupling chemistries for synthesizing a conjugate arewell known in the art and can include, for example, any chemical meansand/or physical means that does not destroy the specific bindingproperty of the specific binding member or the detectable property ofthe label. As used herein, “specific binding member” means a member of abinding pair, e.g., two different molecules where one of the moleculesthrough, for example, chemical or physical means specifically binds tothe other molecule. In addition to antigen and antibody specific bindingpairs, other specific binding pairs include, but are not intended to belimited to, avidin and biotin; haptens and antibodies specific forhaptens; complementary nucleotide sequences; enzyme cofactors orsubstrates and enzymes; and the like.

A polynucleotide is a nucleic acid polymer of ribonucleic acid (RNA),deoxyribonucleic acid (DNA), modified RNA or DNA, or RNA or DNA mimetics(such as, without limitation PNAs), and derivatives thereof, andhomologues thereof. Thus, polynucleotides include polymers composed ofnaturally occurring nucleobases, sugars and covalent internucleoside(backbone) linkages as well as polymers having non-naturally-occurringportions that function similarly. Such modified or substituted nucleicacid polymers are well known in the art and for the purposes of thepresent invention, are referred to as “analogues.” For ease ofpreparation and familiarity to the skilled artisan, polynucleotides arepreferably modified or unmodified polymers of deoxyribonucleic acid orribonucleic acid.

Polynucleotide analogues that are useful include polymers with modifiedbackbones or non-natural internucleoside linkages. Modified backbonesinclude those retaining a phosphorus atom in the backbone, such asphosphorothioates, chiral phosphorothioates, phosphorodithioates,phosphotriesters, aminoalkylphosphotriesters, methyl and other alkylphosphonates, as well as those no longer having a phosphorus atom, suchas backbones formed by short chain alkyl or cycloalkyl internucleosidelinkages, mixed heteroatom and alkyl or cycloalkyl internucleosidelinkages, or one or more short chain heteroatomic or heterocyclicinternucleoside linkages. An example of such a non-phosphorus containingbackbone is a morpholino linkage (see, for example, U.S. Pat. Nos.5,185,444, 5,034,506, and 5,142,047 all of which are herein incorporatedby reference). Modified nucleic acid polymers (analogues) may containone or more modified sugar moieties. For example, sugar moieties may bemodified by substitution at the 2′ position with a 2-methoxyethoxy(2-MOE) group (see, for example, Martin et al., (1995) Helv. Chim. Acta,78:486-504).

Embodiments also contemplate analogues that are RNA or DNA mimetics, inwhich both the sugar and the internucleoside linkage of the nucleotideunits are replaced with novel groups. In these mimetics the base unitsare maintained for hybridization with the target sequence. An example ofsuch a mimetic, which has been shown to have excellent hybridizationproperties, is a peptide nucleic acid (PNA) (Nielsen et al., (1991)Science, 254:1497-1500; International Patent Application WO 92/20702,herein incorporated by reference). In PNA compounds, the sugar-backboneof an oligonucleotide is replaced with an amide containing backbone, forexample an aminoethylglycine backbone. The nucleobases are retained andare bound directly or indirectly to the aza-nitrogen atoms of the amideportion of the backbone.

Contemplated polynucleotides may further include derivatives wherein thenucleic acid molecule has been covalently modified by substitution,chemical, enzymatic, or other appropriate means with a moiety other thana naturally occurring nucleotide, for example with a moiety thatfunctions as a label, as described herein.

The present invention further encompasses homologues of thepolynucleotides having nucleic acid sequences set forth in SEQ ID NOs:1-9 or 10-36. Homologues are nucleic acids having at least onealteration in the primary sequence set forth in any one of SEQ ID NOs:1-9 or 10-36, that does not destroy the ability of the polynucleotide tospecifically hybridize with a target sequence, as described above.Accordingly, a primary sequence can be altered, for example, by theinsertion, addition, deletion or substitution of one or more of thenucleotides of, for example, SEQ ID NOs: 1-9 or 10-36. Thus, homologuesthat are fragments of a sequence disclosed in SEQ ID NOs: 1-9 or 10-36may have a consecutive sequence of at least about 7, 10, 13, 14, 15, 16,17, 18, 19 20, 21, 22, 23 or more nucleotides of the nucleic acidsequences of SEQ ID NO: 1-9 or 10-36, and will retain the ability tospecifically hybridize with a target sequence, as described above.Ordinarily, the homologues will have a nucleic acid sequence having atleast about 50%, 60%, 70%, 80%, 85%, 90% or 95% nucleic acid sequenceidentity with a nucleic acid sequence set forth in SEQ ID NOs: 1-9 or10-36. Identity with respect to such sequences is defined herein as thepercentage of nucleotides in the candidate sequence that are identicalwith the known polynucleotides after aligning the sequences andintroducing gaps, if necessary, to achieve the maximum percent identity.Terminal (5′ or 3′) or internal deletions, extensions or insertions intothe nucleotide sequence shall not be construed as affecting identity.

In some embodiments, the polynucleotides comprise primers and probesthat specifically hybridize to an MTB target sequence, for example thenucleic acid molecules having any one of the nucleic acid sequences setforth in SEQ ID NOs: 1-9 or 10-36, including analogues and/orderivatives of said nucleic acid sequences, and homologues thereof, thatcan specifically hybridize with an MTB target sequence. As describedbelow, polynucleotides find use as primers and/or probes to amplify ordetect MTB.

The polynucleotides can be prepared by a variety of techniques. Forexample, the polynucleotides can be prepared using solid-phase synthesisusing commercially available equipment, such as that available fromApplied Biosystems USA Inc. (Foster City, Calif.), DuPont, (Wilmington,Del.), or Milligen (Bedford, Mass.). Modified polynucleotides, such asphosphorothioates and alkylated derivatives, can also be readilyprepared (see, for example, U.S. Pat. Nos. 5,464,746; 5,424,414; and4,948,882).

The polynucleotides can be employed directly as probes for thedetection, or quantitation, or both, of MTB nucleic acids in a testsample. The test sample is contacted with at least one of thepolynucleotides under suitable hybridization conditions and thehybridization between the target sequence and at least one of thepolynucleotides is then detected. Detection can be direct or indirect.In some embodiments, a hybrid between the probe and target is detecteddirectly. In some embodiments, the hybrid is directed indirectly, forexample, by detecting reaction byproducts generated by an enzymaticreaction that occurs in the presence of a duplex between a probe and theMTB target.

The polynucleotides may incorporate one or more detectable labels.Detectable labels are molecules or moieties having a property orcharacteristic that can be detected directly or indirectly and arechosen such that the ability of the polynucleotide to hybridize with itstarget sequence is not adversely affected.

Detection labels have the same definition as “labels” previously definedand “capture labels” are typically used to separate extension products,and probes associated with any such products, from other amplificationreactants. Specific binding members (as previously defined) are wellsuited for this purpose. Also, probes used according to this method maybe blocked at their 3′ ends so that they are not extended underhybridization conditions. Methods for preventing extension of a probeare well known and are a matter of choice for one skilled in the art.

In cases where labels are employed to detect primer-amplified products,primer sequences optionally can be labeled with either a capture labelor a detection label. In some embodiments, primer comprise a 3′ portionthat hybridizing to an MTB target nucleic acid and a 5′ portion thatintroduces a non-MTB sequence to extension products generated therefrom.Such 5′ portions may include a synthetic tag sequence for use, forexample, in next-generation sequencing technologies.

In some embodiments, a probe is used to hybridize with the extensionproduct or amplicon generated by the primer sequences, and typicallyhybridizes with a sequence that does not include the primer sequences.Similarly to the primer sequence, the probe sequence can also labeledwith either a capture label or a detection label with the caveat that,in some embodiments, when the primer is labeled with a capture label,the probe is labeled with a detection label, and vice versa. Uponformation of the copy sequence/probe hybrids, the differential labels(i.e., capture and detection labels) on the copy sequence and probesequence can be used to separate and detect such hybrids.

The polynucleotides are also suitable for use as capture probes insandwich-type assays. Briefly, the polynucleotide capture probe isattached to a solid support and brought into contact with a test sampleunder suitable hybridization conditions such that a probe:target hybridis formed between the capture probe and any target nucleic acid presentin the test sample. After one or more appropriate washing steps, theprobe:target hybrid is detected, usually by means of a second“disclosure” probe or by a specific antibody that recognizes the hybridmolecule.

Embodiments also contemplate the use of the polynucleotides in modifiednucleic acid hybridization assays. For example, U.S. Pat. No. 5,627,030discloses a method to amplify the detection signal in a nucleic acidhybridization assay. In the disclosed assay, a first polynucleotideprobe sequence is hybridized under suitable conditions to a targetsequence, the probe:target hybrid is subsequently immunocaptured andimmobilized. A second polynucleotide probe which contains many repeatingsequence units is then hybridized to the probe component of theprobe:target hybrid. Detection is achieved by hybridization of manylabeled nucleic acid sequence probes, one to each of the repeatingsequence units present in the second probe. The attachment of multiplelabeled probes to the second probe thus amplifies the detection signaland increases the sensitivity of the assay.

Amplification and Detection of MTB Nucleotide Sequences

The polynucleotides can be used as primers or probes to amplify and/ordetect MTB in a test sample. The primer/probe sets provided hereincomprise at least two primers and at least one probe. These primer/probesets can be employed according to nucleic acid amplification techniques.Hence, the primers in any particular primer/probe set can be employed toamplify a target sequence. In most cases, the probe hybridizes to thecopies of the target sequence generated by one or more of the primersand generally facilitates detecting any copies of the target sequencegenerated during the course of the amplification reaction. All of theprimer/probe sets can be employed according to nucleic acidamplification procedures to specifically and sensitively detect MTB whenthe appropriate primers and probes are combined. It is contemplated thatthe individual primers and probes of the primer/probe sets providedherein may alternatively be used in combination with primers and/orprobes other than those described in the primer/probe sets providedherein. In some embodiments, two primer and probes sets are employed todetect two different MTB target sequences.

Amplification procedures include, but are not limited to, polymerasechain reaction (PCR), TMA, rolling circle amplification, nucleic acidsequence based amplification (NASBA), and strand displacementamplification (SDA). One skilled in the art will understand that for usein certain amplification techniques the primers may need to be modified,for example, for SDA the primer comprises additional nucleotides nearits 5′ end that constitute a recognition site for a restrictionendonuclease. Similarly, for NASBA the primer comprises additionalnucleotides near the 5′ end that constitute an RNA polymerase promoter.

In some embodiments, certain criteria are taken into consideration whenselecting a primer for an amplification reaction. For example, when aprimer pair is required for the amplification reaction, the primersshould be selected such that the likelihood of forming 3′ duplexes isminimized, and such that the melting temperatures (T_(M)) aresufficiently similar to optimize annealing to the target sequence andminimize the amount of non-specific annealing.

In some embodiments, the amplification methods comprises (a) forming areaction mixture comprising nucleic acid amplification reagents, atleast one primer/probe set, and a test sample suspected of containing atleast one target sequence and (b) subjecting the mixture toamplification conditions to generate at least one copy of a nucleic acidsequence complementary to the target sequence. Step (b) of the abovemethods can be repeated any suitable number of times (prior to step (c)in the detection method), e.g., by thermal cycling the reaction mixturebetween 10 and 100 times, typically between about 20 and about 60 times,more typically between about 25 and about 45 times.

Nucleic acid amplification reagents include but are not limited to, anenzyme having at least polymerase activity, enzyme cofactors such asmagnesium or manganese; salts; nicotinamide adenine dinucleotide (NAD);and deoxynucleotide triphosphates (dNTPs) such as for exampledeoxyadenine triphosphate, deoxyguanine triphosphate, deoxycytosinetriphosphate and deoxythymine triphosphate.

Amplification conditions are conditions that generally promote annealingand extension of one or more nucleic acid sequences.

Specific amplicons produced by amplification of target nucleic acidsequences using the polynucleotides, as described above, can be detectedby a variety of methods. For example, one or more of the primers used inthe amplification reactions may be labeled such that an amplicon can bedirectly detected by conventional techniques subsequent to theamplification reaction. Alternatively, a probe consisting of a labeledversion of one of the primers used in the amplification reaction, or athird polynucleotide distinct from the primer sequences that has beenlabeled and is complementary to a region of the amplified sequence, canbe added after the amplification reaction is complete. The mixture isthen submitted to appropriate hybridization and wash conditions and thelabel is detected by conventional methods.

The amplification product produced as above can be detected during orsubsequently to the amplification of the target sequence. Methods fordetecting the amplification of a target sequence during amplification(e.g., real-time PCR) are outlined above, and described, for example, inU.S. Pat. No. 5,210,015. Alternatively, amplification products arehybridized to probes, then separated from other reaction components anddetected using microparticles and labeled probes.

It will be readily appreciated that a procedure that allows bothamplification and detection of target nucleic acid sequences to takeplace concurrently in a single unopened reaction vessel would beadvantageous. Such a procedure avoids the risk of “carry-over”contamination in the post-amplification processing steps, and alsofacilitates high-throughput screening or assays and the adaptation ofthe procedure to automation. Furthermore, this type of procedure allows“real-time” monitoring of the amplification reaction as well as“end-point” monitoring. Examples of probe molecules that areparticularly well-suited to this type of procedure include molecularbeacon probes and TAQMAN probes. TAQMAN probes are generallydual-labeled fluorogenic nucleic acid probes composed of apolynucleotide complementary to the target sequence that is labeled atthe 5′ terminus with a fluorophore and at the 3′ terminus with aquencher. In the free probe, the close proximity of the fluorophore andthe quencher ensures that the fluorophore is internally quenched. Duringthe extension phase of the amplification reaction, the probe is cleavedby the 5′ nuclease activity of the polymerase and the fluorophore isreleased. The released fluorophore can then fluoresce and thus producesa detectable signal.

In some embodiments, “molecular beacon” probes are employed. Molecularbeacon probes are described, for example, in U.S. Pat. Nos. 6,150,097;5,925,517 and 6,103,476 (herein incorporated by reference in theirentireties). Basically, molecular beacons are polynucleotide probescapable of forming a stem-loop (hairpin) structure. The loop is asingle-stranded structure containing sequences complementary to thetarget sequence, whereas the stem typically is unrelated to the targetsequence and self-hybridizes to form a double-stranded region.Nucleotides that are both complementary to the target sequence and thatcan self-hybridize may also form part of the stem region. Attached toone arm of the stem is a fluorophore moiety and to the other arm aquencher moiety. When the polynucleotide adopts a hairpin shape, thefluorophore and the quencher are in close proximity and the energyemitted by the fluorophore is thus absorbed by the quencher and givenoff as heat, resulting in internal quenching of the fluorophore. Uponbinding of the polynucleotide to its target sequence, the fluorophoreand the quencher become spatially separated and the fluorophore canfluoresce producing a detectable signal.

Examples of fluorophores that find use include, but are not limited to,fluorescein and fluorescein derivatives such as a dihalo-(C₁ toC₈)dialkoxycarboxyfluorescein,5-(2′-aminoethyl)aminonaphthalene-1-sulphonic acid (EDANS), coumarin andcoumarin derivatives, Lucifer yellow, Texas red, tetramethylrhodamine,tetrachloro-6-carboxyfluoroscein, 5-carboxyrhodamine, cyanine dyes andthe like. Quenchers include, but are not limited to, DABCYL,4′-(4-dimethylaminophenylazo)benzoic acid (DABSYL),4-dimethylaminophenylazophenyl-4′-maleimide (DABMI),tetramethylrhodamine, carboxytetramethylrhodamine (TAMRA), Black HoleQuestion (BHQ) dyes and the like.

In some embodiments, quantitative assays are employed. In some suchembodiments, an internal standard is employed in the reaction. Suchinternal standards generally comprise a control target nucleic acidsequence and a control polynucleotide probe. The internal standard canoptionally further include an additional pair of primers. The primarysequence of these control primers may be unrelated to the MTBpolynucleotides and specific for the control target nucleic acidsequence. Alternatively, no additional primer need be used if thecontrol target sequence is designed such that it binds the MTB primers.The amount of target nucleic acid in a test sample can be quantifiedusing “end point” methods or “real time” methods.

In some embodiments, MTB detection assays are provided ashigh-throughput assays. For high-throughput assays, reaction componentsare usually housed in a multi-container carrier or platform, such as amulti-well microtiter plate, which allows a plurality of assay reactionscontaining different test samples to be monitored in the same assay. Insome embodiments, highly automated high-throughput assays are employedto increase the efficiency of the screening or assay process. Manyhigh-throughput screening or assay systems are now availablecommercially, as are automation capabilities for many procedures such assample and reagent pipetting, liquid dispensing, timed incubations,formatting samples into microarrays, microplate thermocycling andmicroplate readings in an appropriate detector, resulting in much fasterthroughput times. In some embodiments, reactions are performed inmicrofluidic devices (e.g., cards).

The polynucleotides, methods, and kits are useful in clinical orresearch settings for the detection and/or quantitation of MTB nucleicacids. Thus, in these settings the polynucleotides can be used in assaysto diagnose MTB infection in a subject, or to monitor the quantity of anMTB target nucleic acid sequence in a subject infected with MTB.Monitoring the quantity of bacteria in a subject is particularlyimportant in identifying or monitoring response to anti-bacterialtherapy.

In some embodiments, a dual target assay is performed using real-timePCR, combined with sample inactivation. While a variety of sample may beused, highly clinically relevant sample include smear positive or smearnegative specimens of sputum (induced or expectorated), bronchoalveolarlavage (BAL) samples, or N-Acetyl-LCysteine (NALC)-treated sediments ofsputum and BAL samples. Challenges presented with these samples includethe molecular complexity of sputum, which contains numerous componentsthat can interfere with molecular assays, cell lysis, and cellinactivation.

In some embodiments, a sample inactivation step is performed to reducethe infection risk associated with clinical specimens that may containMTB. Reduction of infection risk is achieved, for example, by incubatingclinical samples with inactivation reagent (see Example 3, below).

In some embodiments, the assays are amenable for use with automatedreal-time PCR detection system, such as the Abbott m2000sp system. Thus,in some embodiments, prior to conducting an assay, the samples areprepared for use with such systems. For example, in some embodiments,preparation of target DNA is performed using a magneticmicroparticle-based technology (Abbott mSample Preparation SystemDNA).This can be performed using an Abbott m2000sp for automated samplepreparation or using a manual sample preparation protocol. In someembodiments, an internal control (IC), positive control, and negativecontrol are processed from the start of sample preparation todemonstrate that the process has proceeded correctly.

For amplification, in some embodiments, purified sample DNA and mastermix are added to a 96-well PCR plate using an Abbott m2000sp instrumentor manually. After addition, each plate is sealed and transferred to anAbbott m2000rt where PCR amplification is performed using DNAPolymerase.

In some embodiments, the presence of MTB amplification products isdetected during the annealing/extension step by measuring the real-timefluorescence signal of the MTB probes. The presence of IC amplificationproducts is detected by measuring the real-time fluorescence signal ofthe IC probe. In some embodiments, the MTB and IC probes aresingle-stranded DNA oligonucleotides consisting of the target-specificbinding sequence, a fluorescent moiety covalently linked to the 5′ endof the probe, and a quenching moiety covalently linked to the 3′ end ofthe probe. In the absence of the MTB or IC target sequences, probefluorescence is quenched. In the presence of MTB or IC target sequences,the MTB or IC probes specifically bind to their complementary sequencesin the targets during the annealing/extension step, allowing fluorescentemission and detection. In some embodiments, the MTB probes are labeledwith different fluorescent dyes (FAM™ for MTB target probes, Quasar® forIC), thus allowing the amplification products of MTB and IC to besimultaneously detected in the same reaction.

In some embodiments, steps are taken to avoid nucleic acidcontamination. For example, in some embodiments, contamination isminimized because: PCR amplification and oligonucleotide hybridizationoccur in a sealed multi-well plates; detection is carried outautomatically without the need to open the reaction vessels (e.g., platewells); aerosol barrier pipette tips are used for all pipetting; thepipette tips are discarded after use; and separate dedicated areas areused to perform the MTB assay.

In some embodiments, the above reagents are provided in the form of akit and/or system (e.g., systems comprising automated sample handlingand assay instruments described herein). For example, in someembodiments, the kit comprises, consists essentially of, or consists of:

-   -   1. MTB Internal Control (4 vials, 0.4 mL per vial)<0.01%        noninfectious linearized DNA plasmid in a buffer solution with        carrier DNA. Preservatives: Sodium azide and 0.15% ProClin® 950.    -   2. Amplification Reagent Pack (4 packs, 24 tests/pack). Each        Reagent Pack contains: 1 bottle (0.078 mL) DNA Polymerase (5.4        to 5.9 units/μL) in buffered solution with stabilizers. 1 bottle        (0.5314 mL) MTB Amplification Reagent. <0.1% synthetic        oligonucleotides (one or more target primer sets and probes; a        primer set and probe for the internal control), and <0.6% dNTPs        in a buffered solution with a reference dye. Preservatives:        Sodium azide and 0.15% ProClin® 950. 1 bottle (0.778 mL)        Activation Reagent. 38 mM magnesium chloride in a buffered        solution. Preservatives: Sodium azide and 0.15% ProClin® 950.    -   3. MTB Negative Control (8 vials, 1.6 mL per vial); Buffered        solutions; Preservatives: Sodium azide and 0.15% ProClin® 950.    -   4. MTB Positive Control (8 vials, 1.6 mL per vial); <0.01%        noninfectious linearized DNA plasmid in a buffer solution with        carrier DNA. Preservatives: Sodium azide and 0.15% ProClin® 950.

In some embodiments, all forms of MTB are detected (e.g., the primersand probes are selected to identify all MTB nucleic target sequencesthat might be present in a sample). In some embodiments, specific MTBsequences are detected, such as antibiotic-resistant strains (e.g.,rifampicin, isoniazid).

EXAMPLES

The following examples are for illustrative purposes only and should notbe construed to limit the scope of this invention in any way.

Example 1 Exemplary Assay Workflow

This example describes a specific, efficient approach to conductingreal-time PCR to detect MTB in a sample. In some embodiments, real-timePCR methods comprise or consist of the following steps:

-   -   1. Inactivation of MTB in samples (e.g., sputum, bronchoalveolar        lavage [BAL], and N-acetyl-L-cysteine [NALC] sediments of sputum        and BAL) using an inactivation reagent (IR). In some        embodiments, the inactivation reagent comprises or consists        isopropanol, sodium hydroxide, TWEEN-20, and water;    -   2. Sample preparation in which DNA is extracted from the        inactivated samples using reagents; sample preparation is        performed using the automated m2000sp instrument (Abbott        Molecular), or manually;    -   3. PCR assembly in which purified samples and assay PCR        components are added together in a 96-well optical reaction        plate or other multi-chamber reaction support; this is performed        using the m2000sp or manually;    -   4. Manual sealing of the 96-well optical reaction plate and        transfer of the plate to an m2000rt instrument.    -   5. Amplification and detection of PCR products using the        automated m2000rt instrument; patient results are automatically        reported on the m2000rt workstation. A graphical summary of this        workflow is shown in FIG. 1.

Example 2 Target Selection and Primer/Probe Design

In some embodiments, a dual target strategy is employed for detectingMTB complex. The two targets include: Insertion sequence (IS) 6110 andProtein Antigen B (PAB). See Table 1 below:

TABLE 1 Abbott RealTime MTB target selection: IS6110 Insertion sequence(IS) of the IS3 category Usually present in multiple copies per cell(e.g. Denmark, 50% 11-15 copies per cell) Some TB strains have no or lowcopy numbers of IS6110 PAB Single copy gene coding for protein antigen b

Used of a dual target strategy prevents false negative results caused bytarget sequences mutation or deletion.

Probes and primers that find use in the detection of IS6110 and PABtarget sequences include those in Table 2.

TABLE 2 RealTime MTB primer/probe sequences: Material SEQ ID NO SequenceIS6110 SEQ ID NO: 1 5′ CCT GCG AGC GTA GGC (121) FP GTC GGT GA 3′ IS6110SEQ ID NO: 2 5′ CGT CCA GCG CCG CTT (121) RP CGG ACC A 3′ PAB abt2SEQ ID NO: 3 5′ GCA CCT CAA GCT GAA FPb CGG AAA AGT CCT 3′ PAB abt2SEQ ID NO: 4 5′ CCG GGG TTG AGC GCA RPx GCG ATC T 3′ IS6110 SEQ ID NO: 55′ 6-Fam-pdU#AG GpdUG probe6 AGG pdUpdC*pdU GpdCpdUApdCpdC pdC-BHQ1 dT 3′ PAB SEQ ID NO: 6 5′ 6-Fam-pdUApdC pdCAG probe 1GGpdC ApdCpdC ApdUpdC AAA-BHQ1 dT 3′ IC FP 196 SEQ ID NO: 7 5′CTA CAG CAG AGT TGG CAG CTT CAC TTT C 3′ IC RP 310 SEQ ID NO: 8 5′GTC TGG CCT TTC AGC AAG TTT C 3′ Internal SEQ ID NO: 9 5′Quasar-GApdC GAG  Control pdUpdUpdC ApdUG AGG Probe: GpdCA-BHQ2 dT 3′(FP = forward primer; RP = reverse primer; #pdU = 5′ propynyl dU; *pdC =5′ propynyl dC; Fam = fluorescein dye; BHQ = Black Hole Quencher; IC =internal control)

Table 3 provides alternative primers and probes for use in the detectionMTB target sequences. In addition to IS6110 and PAB, additional targetsinclude rPOB (single copy gene coding for β subunit of RNA polymerase,site of about 95% of rifampicin-resistance mutations), SenX3-RegXe(single copy gene coding for regulatory proteins), hsp65 (single copygene coding for heat shock protein), and MPB64 (single copy gene codingfor 23 KDA protein). Table 3. Other primer/probe sequences:

Name SEQ ID NO Sequences IS6110 (104) FP1 SEQ ID NO: 10 5′ GCCGCTTCGGACCACCAGCACCTAAC IS6110 (104) RP1 SEQ ID NO: 11 5′ GTAGGCGTCGGTGACAAAGGCCACGTAG IS6110 (104) probe SEQ ID NO: 12 5′ TGCCCAGGTCGAC ACATAIS6110 (80) FP1 SEQ ID NO: 13 5′ TACGACCACATCA ACCGGGAGCCCAIS6110 (80) RP1 SEQ ID NO: 14 5′ GCGTGGACGCGGC TGATGTGCTCCTIS6110 (80) pr1 SEQ ID NO: 15 5′ CCGCGAGCTGCGC GATG PAB abt1 FPSEQ ID NO: 16 5′-GCACGCTGCTCTA CCCGCTGTTCAACCT PAB abt1 RP SEQ ID NO: 175′-GTGCCCTGAGCGG TGATCGTGACGTT PAB abt1 Probe: SEQ ID NO: 18 5′TCCGGCCTTTCAC GAGA nhsp65 FP1 SEQ ID NO: 19 5′ TCGGGGCTCGGGT AGAAGTTnhsp65 RP1 SEQ ID NO: 20 5′ TCGTCAACTCGGG CAGCAAC nhsp65 probe 1SEQ ID NO: 21 5′ TACTCGGCTCACG CACG vhsp65 FP1 SEQ ID NO: 22 5′GGCTCGGGTAGAA GTTCGACTTGG vhsp65 RP1 SEQ ID NO: 23 5′ GTCAACTCGGGCAGCAACGAC vhsp65 probe 1 SEQ ID NO: 24 5′ CTCACGCACGGCG GTATTC senX3 FPSEQ ID NO: 25 5′ GGCAGCGGACTCG GGTT senX3 RP SEQ ID NO: 26 5′ACCGCAGTTCGGG CTCTC senX3 Pr SEQ ID NO: 27 5′ TCACGACGACGAG CGACregX3 FP SEQ ID NO: 28 5′ CGCTGATGACCAG TGTGTTGATT regX3 RPSEQ ID NO: 29 5′ GCAGCATCAGATC GAGCAGGAC regX3 Probe SEQ ID NO: 30 5′ATGGTCCGGCAGC TCTC MPB64 FP1 SEQ ID NO: 31 5′ CAACATCAGCCTGCCCAGTTACTACC MPB64 RP1 SEQ ID NO: 32 5′ CTTCGCGTGGAGT GGACGATGMPB64 Probe1 SEQ ID NO: 33 5′ AAGTCGCTGGAAA ATTACAT rPOB FPaSEQ ID NO: 34 5′ CGTGGAGGCGATC ACACCGCAGACGTT rPOB RPb SEQ ID NO: 35 5′CGTTGATCAACAT CCGGCCGGTGGTC rPOB probe5 SEQ ID NO: 36 5′ CGGTCTGTCACGTGAGCGTGC

Example 3 Sample Inactivation

This example describes exemplary reagents and methods for conducting asample inactivation step.

Preparation of Inactivation Reagent (IR)

Materials Employed:

-   -   Polypropylene or glass container    -   10M NaOH    -   Isopropanol    -   TWEEN-20    -   Purified water

Preparation of IR:

-   -   Material Volume Required for 500 mL        -   10M NaOH 20 mL        -   Purified water 179.1 mL        -   Isopropanol 300 mL        -   TWEEN-20 0.9 mL            1. Add 179.1 mL of water to an empty polypropylene or glass            container (avoid use of a polystyrene container).            2. Add 0.9 mL of TWEEN-20 to the container.            3. Add 20 mL of 10M NaOH to the container.            4. Add 300 mL of isopropanol to the container.            5. Mix the components by inversion 20 times.            Use or store at ambient temperature for up to 1 month.

Inactivation Procedure:

1. If frozen, thaw specimens at 15 to 30° C.

2. Estimate the volume of specimen to be inactivated.

3. Add IR at a ratio of 1:3 (e.g., 1 mL specimen+3 mL IR) (the preferredspecimen volume is 0.3 to 10 mL).

4. Invert the container to ensure contact between the IR and thespecimen.

5. Vortex the mixture for 20 to 30 seconds.

6. Incubate the mixture at ambient temperature for at least 1 hour andpreferably no more than 24 hours. Vortex the mixture one final time for20 to 30 seconds at 20 to 30 minutes into the incubation period.

Example 4 Sample Preparation Method

The MTB assay of Example 1 uses an Abbott automated m2000sp instrumentor manual method for processing sputum, BAL and NALC-NaOH sediment ofsputum or BAL samples and uses an Abbott automated m2000rt instrumentfor amplification and detection. Both processes entail DNA extractionfrom samples, both DNA purifications are performed using the DNA GPR(List 6K12-24) sample preparation reagents from the Abbott mSamplePreparation System_(DNA).

The sample preparation reagents and method (including lyses step, washstep, elution step, tip reuse arrangement etc.) were optimized to reducethe inhibitory effect on PCR reactions due to the inhibitory sputum orcarryover of TB Inactivation reagent (IR): thus centrifugation to getrid of IR in the IR treated sample is not necessary. The procedure isalso optimized to reduce carryover from high positives to nearbynegative sample. The sample preparation is also optimized to ensure TBcell breakage for efficient DNA recovery and PCR.

Real-Time PCR:

After PCR reaction assembly in a 96-well optical reaction plate (eithermanually or via the m2000sp), the 96-well plate is manually sealed andtransferred to the m2000rt to perform the amplification and real-timefluorescence detection reaction. Patient results are automaticallyreported on the m2000rt workstation. The MTB assay detects an internalcontrol nucleic acid sequence as sample validity control, sampleextraction and amplification efficiency control. Table 4 providesexemplary PCR cycling conditions.

TABLE 4 Stage Cycle Step Temperature (° C.) Time 1 1 1 50 10 min 2 1 194 10 min 3 50 1 94 35 sec 2 64 15 sec Read 3 65 40 sec

For the data shown in the below examples, an assay cutoff of 42 wasused. That is samples with Ct values<42 are considered to be MTBDetected, while samples with assay Ct values>42 are considered MTB NotDetected.

Assays run on the m2000rt are per the manufacturer's recommendprotocols. One such example includes the steps of:

1. 96 IR-treated samples are performed per run. One negative control and1 positive control are included in each run, therefore allowing amaximum of 94 IR-treated samples to be processed per run.

2. Before use, vortex IR-treated samples for 3 to 5 seconds. Using apipette, transfer the IR-treated samples to the reaction vessels.Minimize the transfer of visible particulates in the IR-treated samplesduring this step.

3. Thaw assay controls, IC, and amplification reagents at 2 to 8° C. or15 to 30° C. Once thawed, IC can be stored closed at 2 to 8° C. for upto 14 days prior to use. Once thawed, controls can be stored at 2 to 8°C. for up to 24 hours prior to use. If not using the optionalamplification reagent extended use feature: Thaw new amplificationreagents at 2 to 8° C. or 15 to 30° C. Once thawed, the amplificationreagents can be stored at 2 to 8° C. for up to 24 hours, prior to use.If using the optional amplification reagent extended use feature: Selectnew and/or partial amplification reagent packs to be used in the run.Refer to Abbott m2000sp Operations Manual (List No. 9K20-06 or higher),Operating Instructions, for instructions pertaining to amplificationreagent pack inventory management. Amplification reagent packs shouldhave the same lot number.

4. Vortex each control 3 times for 2 to 3 seconds each time before use.Ensure that bubbles or foam are not created. If found, remove them witha new sterile pipette tip for each tube. Ensure that the contents ofeach vial are at the bottom after vortexing by tapping the vials on thebench to bring liquid to the bottom of the vial.

5. Gently invert the Abbott mSample Preparation SystemDNA bottles toensure a homogeneous solution. If crystals are observed in any of thereagent bottles upon opening, allow the reagent to equilibrate at roomtemperature until the crystals disappear. Do not use the reagents untilthe crystals have dissolved. Ensure bubbles or foam are not generated;if present, remove with a sterile pipette tip, using a new tip for eachbottle. NOTE: Before pouring the mMicroparticlesDNA into the 200 mLreagent vessel, vigorously mix or vortex until the mMicroparticlesDNAare fully resuspended.

6. Vortex the IC vial 3 times for 2 to 3 seconds each time before use.Ensure bubbles or foam are not generated; if present, remove with asterile pipette tip.

7. Using a calibrated precision pipette dedicated for internal controluse only, add 180 μL of IC to 1 bottle of mLysisDNA buffer. Mix bygently inverting the container 5 to 10 times to minimize foaming. Eachbottle of mLysisDNA buffer supports up to 48 sample preparations. Add180 μL of IC to a second bottle of mLysisDNA buffer for 49 to 96samples. If using the optional amplification reagent extended usefeature, partial vials of IC can be recapped and stored at 2 to 8° C.for a second use.

8. Add 25 mL of USP grade 190 to 200 proof ethanol (95 to 100% ethanol)to the mLysisDNA buffer+IC reagent bottle. Do not use ethanol thatcontains denaturants. Gently invert the container to ensure homogeneoussolution. For 49 to 96 samples, add 25 mL of ethanol to a second bottleof mLysisDNA buffer+IC. Gently invert to ensure a homogeneous solution.

9. Add 70 mL USP grade 190 to 200 proof ethanol (95 to 100% ethanol) tomWash 2DNA bottle. Do not use ethanol that contains denaturants. Eachbottle of mWash 2DNA supports up to 48 reactions. Gently invert toensure a homogeneous solution.

10. Place the negative and positive control and the patient specimensinto the Abbott m2000sp sample rack.

11. Place the 5 mL Reaction Vessels into the Abbott m2000sp 1 mLsubsystem carrier.

12. Load the carrier racks containing the Abbott mSample PreparationSystemDNA reagents and the Abbott 96-Deep-Well Plate on the Abbottm2000sp worktable as described in the Abbott m2000sp Operations Manual,Operating Instructions.

13. From the Run Sample Extraction screen, select and initiate thesample extraction protocol as described in the Abbott m2000sp OperationsManual, Operating Instruction. NOTE: Change gloves before handling theamplification reagents.

14. Load the amplification reagent pack and master mix vial (if needed)on the Abbott m2000sp worktable after sample preparation is completed.Each amplification reagent pack supports up to 24 reactions. Thaw 1 setof reagents for 1 to 24 samples, 2 sets for 25 to 48 samples, 3 sets for49 to 72 samples and 4 sets for 73 to 96 samples. Ensure theamplification reagents are thoroughly thawed before use. Ensure that thecontents are at the bottom of the vials by tapping the vials in anupright position on the bench. Remove the amplification reagent vialcaps. If using the optional amplification reagent extended use feature,a combination of new and partial reagent packs may be used. If not usingthe optional amplification reagent extended use feature, only newreagent packs may be used. Ensure that the contents of new amplificationreagent packs are at the bottom of the vials prior to opening theamplification reagents by tapping the vials in an upright position onthe bench. Do not tap partial amplification reagent packs being used asecond time. Tapping may result in loss of master mix volume in the cap.Remove caps. If a new amplification reagent pack is stored for a seconduse, the vials are recapped for storage. If planning to reuse theoriginal caps to recap the reagent vials, the original caps are savedand used. If planning to use fresh caps to recap the reagent vials,original caps are discarded. Partial amplification packs are loaded tothe left of new amplification packs on the Abbott m2000sp worktable.Ensure that the amplification reagent packs are firmly seated on theinstrument.

15. Select the appropriate deep-well plate from the Run Master MixAddition screen that matches the corresponding sample preparationextraction. Initiate the Abbott m2000sp Master Mix Addition protocol.Follow the instructions as described in the Abbott m2000sp OperationsManual, Operating Instructions section. NOTE: The assembly of theamplification master mix and sample eluates into the Abbott 96-WellOptical Reaction Plate (step 15) should be initiated within 1 hour aftercompletion of Sample Preparation. NOTE: The Abbott m2000rt protocol(step 20) should be started within 90 minutes of the initiation of theMaster Mix Addition protocol. NOTE: If the run is aborted for any reasonsubsequent to step 15, the amplification reagents are to be discardedand a new 96-well PCR plate should be used if the Abbott m2000sp MasterMix Addition Protocol (step 15) will be repeated.

16. Switch on and initialize the Abbott m2000rt in the AmplificationArea. NOTE: The Abbott m2000rt requires 15 minutes to warm up. NOTE:Change laboratory coats and gloves before returning to the samplepreparation area.

17. Place the Abbott 96-Well Optical Reaction Plate into the AbbottSplash-Free Support Base after the Abbott m2000sp instrument hascompleted addition of samples and master mix.

18. Seal the Abbott 96-Well Optical Reaction Plate according to theAbbott m2000sp Operations Manual, Operating Instructions section. Exportthe completed PCR plate results to a CD (or directly to a mapped Abbottm2000rt via a network connection).

In some embodiments, a manual sample preparation method is employed. Anexample of such a method is as follows:

1. Thaw amplification reagents at 15 to 30° C. or at 2 to 8° C. Thisstep can be initiated before completion of the sample preparationprocedure.

2. 12 samples are processed per set of magnetic racks. A negativecontrol and a positive control are included in each run, thereforeallowing a maximum of 10 specimens to be processed. Prepare thespecimens for processing by following these steps: NOTE: Patientspecimens should be inactivated prior to beginning sample extraction.

3. Thaw 1 tube of the MTB Negative Control, 1 tube of MTB PositiveControl, and 1 vial of MTB Internal Control at 15 to 30° C. or at 2 to8° C. Once thawed, if IC is not being processed immediately, store at 2to 8° C. for up to 14 days prior to use. Once thawed, if controls arenot being processed immediately, store at 2 to 8° C. for up to 24 hoursprior to use. Vortex controls and IC 3 times for 2 to 3 seconds eachtime before use. Ensure that the contents of each vial are at the bottomafter vortexing by tapping the vials on the bench to bring liquid to thebottom of the vial. Ensure bubbles or foam are not generated; ifpresent, remove with a sterile pipette tip, using a new tip for eachvial.

4. Open the Abbott mSample Preparation SystemDNA reagent pack(s). Ifcrystals are observed in any of the reagent bottles upon opening, allowthe reagent to equilibrate at room temperature until the crystalsdisappear. Do not use the reagents until the crystals have dissolved.

5. Prepare the mWash 2DNA by adding 70 mL of USP grade 190 to 200 proofethanol (95 to 100% ethanol) to the mWash 2DNA bottle. Do not useethanol that contains denaturants. Gently invert to ensure a homogeneoussolution. NOTE: Mark the mWash 2DNA bottle to indicate that ethanol hasalready been added for extended use.

6. Prepare the mLysisDNA by adding 25 mL of USP grade 190 to 200 proofethanol (95 to 100% ethanol) to the mLysisDNA bottle. Do not use ethanolthat contains denaturants. Gently invert 5 to 10 times to mix and tominimize foaming. NOTE: Mark the mLysisDNA bottle to indicate thatethanol has already been added for extended use.

7. Calculate the volume of mLysisDNA solution required for the manualrun: (1.85 mL of mLysisDNA×number of samples). Pipette the requiredvolume of mLysisDNA solution into a polypropylene container large enoughto hold the entire volume. Calculate the volume of IC required for themanual run: (3.51 μL of IC×number of samples). Use a precision pipettededicated to internal control use only to add the required volume of ICinto the polypropylene container containing the mLysisDNA solutionrequired for the manual run. Mix mLysisDNA solution and IC mixture bygentle inversion 10 to 15 times to minimize foaming. After initial use,partial IC vials maybe stored at 2 to 8° C. for up to 14 days and used 1additional time.

8. Gently invert all the reagent bottles, except the mMicroparticlesDNAbottle and the mWash 1DNA bottle, 5 to 10 times to ensure a homogenoussolution prior to use. The mMicroparticlesDNA bottle will be mixed instep 11.

9. Turn on the temperature-controlled dry heating blocks. Set the firstblock to 58° C. Set the second block to 80° C. NOTE: Check thetemperature of the heating blocks. Do not proceed until the heatingblocks are at the correct temperature.

10. Label all necessary tubes: One 5 mL reaction vessel per sample forthe Lysis Incubation and mWash 1DNA steps. One 1.5 mL microfuge tube persample for the first and second mWash 2DNA and Elution steps. One 1.5 mLmicrofuge tube per sample or a 96-well polypropylene plate for theeluate.

11. Place the labeled 5 mL reaction vessels for each sample in unheatedstand. Resuspend mMicroparticlesDNA by vortexing or vigorously shakinguntil particles are in suspension and settled particles are no longerseen on the bottom of the bottle. After the particles are resuspended,use a precision pipettor and a sterile 200 μL aerosol barrier pipettetip to add 50 μL of mMicroparticlesDNA to each reaction vessel.

12. Using a fresh, sterile 1000 μL aerosol barrier pipette tip for eachsample, add 1.75 mL (2×875 μL) of mLysisDNA to the reaction vessels.

13. Add 0.8 mL of the controls, and specimens to the appropriatereaction vessels using a precision pipettor and a fresh, sterile 1000 μLaerosol barrier pipette tip for each sample. Mix each sample/mLysisDNAmixture by aspirating and dispensing the 800 μL volume 5 to 10 timesuntil a uniform suspension is obtained. NOTE: Aspirate and dispenseliquid slowly to avoid foaming.

14. Transfer the 5 mL reaction vessels into the 58° C. heating block.

15. Start the timer and incubate for 15 minutes.

16. After incubation using a fresh, sterile 1000 μL aerosol barrierpipette tip for each sample, mix the mixture 5 times by aspirating anddispensing 800 μL.

17. Start the timer and incubate for an additional 10 minutes in the 58°C. heating block.

18. After incubation using a fresh, sterile 1000 μL aerosol barrierpipette tip for each sample, mix the mixture 5 times by aspirating anddispensing 800 μL.

19. Start the timer and incubate for an additional 10 minutes in the 58°C. heating block.

20. After the incubation is complete, place the reaction vessels in amagnetic capture stand for 2 minutes to allow the particles to becaptured on the side of the reaction vessels.

21. With the reaction vessels in the magnetic capture stand, use afresh, sterile 1000 μL aerosol barrier pipette tip or disposabletransfer pipette for each sample to carefully remove the mLysisDNA fromeach reaction vessel and discard the fluid into a liquid wastecontainer. Remove the fluid as completely as possible. Do not disturb oraspirate the captured magnetic particles.

22. Remove the reaction vessels from the magnetic rack and transfer to anonmagnetic rack. mWash 1DNA (Wash).

23. Using a precision pipettor and a fresh, sterile 1000 μL aerosolbarrier pipette tip for each sample, add 800 μL of mWash 1DNA to thesamples and resuspend the magnetic particles in the wash fluid by gentlymixing 10 times by aspiration and dispense with a pipette tip. Wash theparticles from the side of the reaction vessel, if necessary. NOTE: Whenadding mWash 1DNA wash, dispense liquid slowly to avoid splashing.

24. Transfer the wash fluid and particles to a labeled 1.5 mL microfugetube.

25. Place the tubes in a magnetic capture stand for 1 minute to allowthe particles to be captured on the side of the tubes.

26. With the tubes in the magnetic capture stand, use a fresh, sterile1000 μL aerosol barrier pipette tip for each sample to carefully removethe mWash 1DNA from each tube and discard fluid into a liquid wastecontainer. Remove the fluid as completely as possible. DO NOT disturb oraspirate the captured magnetic particles.

27. Remove the tubes from the magnetic rack and transfer to anonmagnetic rack. mWash 2DNA (First Wash).

28. Using a precision pipettor and a fresh, sterile 1000 μL aerosolbarrier pipette tip for each sample, add 800 μL of mWash 2DNA to thesamples and resuspend the magnetic particles in the wash fluid by gentlymixing 5 to 10 times by aspiration and dispense with a pipette tip. Washthe particles from the side of the tube, if necessary. NOTE: When addingmWash 2DNA wash, dispense liquid slowly to avoid splashing.

29. Place the tubes in a magnetic capture stand for 1 minute to allowthe particles to be captured on the side of the tubes.

30. With the tubes in the magnetic capture stand, use a fresh, sterile1000 μL aerosol barrier pipette tip for each sample to carefully removethe mWash 2DNA from each tube and discard fluid into a liquid wastecontainer. Remove the fluid as completely as possible. DO NOT disturb oraspirate the captured magnetic particles.

31. Remove the tubes from the magnetic rack and transfer to anonmagnetic rack. mWash 2DNA (Second Wash).

32. Using a precision pipettor and a fresh, sterile 1000 μL aerosolbarrier pipette tip for each sample, add 800 μL of mWash 2DNA to thesamples and resuspend the magnetic particles in the wash fluid by gentlymixing 5 to 10 times by aspiration and dispense with a pipette tip. Washthe particles from the side of the tube, if necessary. NOTE: When addingmWash 2DNA wash, dispense liquid slowly to avoid splashing.

33. Place the tubes in a magnetic capture stand for 1 minute to allowthe particles to be captured on the side of the tubes.

34. With the tubes in the magnetic capture stand, use a fresh, sterile1000 μL aerosol barrier pipette tip for each sample to carefully removethe mWash 2DNA from each tube and discard fluid into a liquid wastecontainer. Remove the fluid as completely as possible. DO NOT disturb oraspirate the captured magnetic particles.

35. Remove the tubes from the magnetic rack and transfer to the 80° C.heating block and incubate for 15 minutes with caps open to allow forthe evaporation of the ethanol.

36. Using a precision pipettor and a fresh, sterile 1000 μL aerosolbarrier pipette tip for each sample, add 250 μL of mElution BufferDNA tothe samples and resuspend the magnetic particles in the fluid byaspiration and dispense with the pipette tip. Wash the particles fromthe side of the tube, if necessary.

37. Place the tubes in the 80° C. heating block, start the timer, andincubate for 4 minutes.

38. Remove the tubes from the 80° C. heating block. Using a fresh,sterile 1000 μL aerosol barrier pipette tip for each sample, mix thesample and mElution BufferDNA mixture 4 times by aspirating anddispensing 200 μL.

39. Return the tubes to the 80° C. heating block. Start the timer andincubate for 4 minutes.

40. Remove the tubes from the 80° C. heating block and place in amagnetic capture stand for 1 minute to allow the particles to becaptured on the side of the tubes.

41. With the tubes in the magnetic capture stand, use a fresh, sterile1000 μL aerosol barrier pipette tip for each sample to carefully removethe eluted sample from the tubes. Do not disturb or aspirate thecaptured microparticles. The eluted sample(s) can be placed into afresh, labeled 1.5 mL microfuge tube or a 96-well polypropylene plate.NOTE: The assembly of the amplification master mix and sample eluatesinto the Abbott 96-Well Optical Reaction Plate (step 48) must beinitiated within 1 hour after completion of Sample Preparation.

42. Switch on and initialize the Abbott m2000rt instrument. NOTE: TheAbbott m2000rt requires 15 minutes to warm up.

43. Create the Abbott m2000rt test order. Refer to the OperatingInstructions section of the Abbott m2000rt Operations Manual. From theProtocol screen, select the Abbott RealTime MTB assay applicationprotocol. NOTE: Remove gloves before returning to the reagentpreparation area.

44. Prepare the amplification master mix. NOTE: All reagent preparationshould take place in the dedicated Reagent Preparation Area. Changegloves before handling the amplification reagents. Do not vortex orinvert the amplification reagent pack. Each amplification reagent packsupports up to 24 reactions. Ensure the amplification reagents arethoroughly thawed before use. Prior to opening the amplificationreagents, ensure that the contents of the amplification reagent pack areat the bottom by tapping the amplification reagent pack in an uprightposition on the bench to bring the liquid to the bottom of the vials.Identify the amplification reagents as follows: Activation Reagent(Reagent 1); MTB Amplification Reagent (Reagent 2); DNA Polymerase(Reagent 3); Remove and discard caps. Using a calibrated precisionpipette dedicated for reagent use only, add 298 μL of Activation Reagent(Reagent 1) and 418 μL of MTB Amplification Reagent (Reagent 2) to theDNA Polymerase bottle (Reagent 3) to make master mix. Mix by gentlypipetting up and down 5 times. Avoid creating foam.

45. Pipette the contents of the master mix from the DNA Polymerasebottle into a 1.5 mL microfuge tube (List No. 4J71-50 or equivalent).Mix by gently pipetting up and down 5 times. Avoid creating foam.

46. Place an Abbott 96-Well Optical Reaction Plate in the AbbottSplash-Free Support Base to prevent contamination. Contamination of thebottom of the Abbott 96-Well Optical Reaction Plate with fluorescentmaterials could potentially interfere with the MTB assay. The Abbott96-Well Optical Reaction Plate should be held and transported with theAbbott Splash-Free Support Base to minimize contamination.

47. Using a precision pipette dedicated for reagent use only, dispense25 μL aliquots of the amplification master mix into each well of theAbbott 96-Well Optical Reaction Plate that will be used to run thesamples and controls. A calibrated repeat pipettor may be used. Add themaster mix in an order starting with column 1 (from top to bottom), andmoving to each consecutive column from left to right. Visually verifythat 25 μL has been dispensed into each well. Transfer the Abbott96-Well Optical Reaction Plate in the Abbott Splash-Free Support Base tothe Sample Preparation Area.

48. Using a precision pipettor and a fresh, sterile 200 μL aerosolbarrier pipette tip for each sample, transfer 25 μL of each elutedsample to the Abbott 96-Well Optical Reaction Plate. During the transferof each sample, mix the final reaction by pipetting up and down 3 to 5times. Visually verify that a total of 50 μL has been dispensed intoeach well.

49. Seal the Abbott 96-Well Optical Reaction Plate according to theinstructions in the Abbott m2000rt Operations Manual, OperatingInstructions section.

50. Centrifuge the Abbott 96-Well Optical Reaction Plate in the AbbottSplash-Free Support Base at 5000 g for 5 minutes.

51. Transfer the Abbott 96-Well Optical Reaction Plate in the AbbottSplash-Free Support Base to the Amplification Area. NOTE: The Abbottm2000rt protocol (step 52) should be started within 90 minutes followingthe initiation of the master mix addition and PCR plate preparation(step 44).

52. Place the Abbott 96-Well Optical Reaction Plate in the Abbottm2000rt instrument, select the test order created (step 43), andinitiate the Abbott RealTime MTB assay application protocol, asdescribed in the Abbott m2000rt Operations Manual, OperatingInstructions section. At the completion of the run, assay results arereported on the Abbott m2000rt.

Example 5 Experimental Data—Inactivation

The IR TB killing effectiveness was evaluated. In this experiment,MTB-containing samples (cultured MTB that was diluted to known MTBconcentrations prior to inactivation, as well as MTB-containingNALC-NaOH sediments) were subjected to the inactivation procedure ofExample 3. Following inactivation, excess Inactivation Reagent wasremoved by centrifugation/washing and the surviving cells were placedinto MGIT culture for up to 42 days or six weeks. This duration is therecommended longest time for MTB culture; most MTB positive specimenswill result in detectable culture growth within 20 days of initiation ofculture). Table 5 below illustrates the results obtained when testingthe cultured samples following inactivation. The Positive Control (PC),which consists of non-inactivated MTB, demonstrated growth within theexpected 20-day timeframe, while the Negative Control (NC), showed nogrowth.

TABLE 5 Inactivation of cultured high concentration MTB cells. Reductionof MTB Infection Risk Study Summary Positive Samples Positive SamplesWithout IR Treatment With IR Treatment Number Number Number of Samplesand Samples and Isolate CFU/ Replicates Culture Replicates Culture StudySamples mL Tested Positive Tested Positive 1  3^(a) 1 × 10⁸ 3 × 1 3 of 33 × 3 0 of 9 1 × 10⁷ 3 × 1 3 of 3 3 × 3 0 of 9 1 × 10⁶ 3 × 1 3 of 3 3 ×3 0 of 9 2 20^(b) N/A 20 × 1  20 of 20 20 × 1   0 of 20 3 31^(b) N/A 31× 1  31 of 31 31 × 1   0 of 31 ^(a)Cultured Isolate Samples ^(b)ClinicalIsolate Samples

These data demonstrate the effectiveness of the inactivation procedurefor inactivation of MTB.

Example 6 Analytical Inclusivity

Eight subspecies and 20 samples of MTB complex (M. tuberculosis, M.africanum, M. bovis, M. bovis BCG, M. canettii, M. microti, M. caprae,M. pinnipedii.) were obtained from ATCC (M. canettii was received fromthe Public Health Research Institute) and were tested from 10 to 100genomic DNA copies/reaction (See Table 6). All 8 subspecies weredetected at both levels.

TABLE 6 MTB complex subspecies tested Name Name Mycobacteriumtuberculosis 25177D-5 M pinnipedii BAA-688D (H37Ra) M bovis BCG 35747D Mtuberculosis 25618D-5 (H37Rv) M caprae BAA-824D M microti 11152 Mtuberculosis BAA-2236D M microti 19422 M tuberculosis BAA-2237D Mafricanum 25420 M tuberculosis 27294D M africanum 35711 M tuberculosisBAA-2234D M bovis 35735 M tuberculosis 35822D M bovis 19274 Mtuberculosis 35838D M bovis BCG 35746 M tuberculosis BAA-2235D Mcanettii

Forty six phylogenetically and geographically diverse MTB isolate DNAs(>50% with MDR) obtained from the Public Health Research Institute weretested from 25 to 100 genomic DNA copies/reaction (FIG. 2). Allsubspecies tested were detected.

Example 7 Analytical Specificity

Purified nucleic acid from different mycobacteria, viruses and othermicroorganisms (n=80) at targeted concentrations of 1e5 to 1e7genomes/mL and cultured microorganisms at 1×10⁶ cfu/mL were added to MTBnegative control to evaluate the effect of potential cross-reactants onMTB assay results for MTB negative specimens. Purified nucleic acid fromdifferent mycobacteria, viruses and other microorganisms at targetedconcentrations of 1×10⁶ to 1×10⁷ genomes per milliliter and culturedmicroorganisms at 1e6 cfu/mL were added to MTB positive samples toevaluate the effect of potential cross-reactants on MTB assay resultsfor MTB positive specimens. MTB positive samples were prepared bydiluting heat inactivated MTB cell stock in negative control to atargeted concentration of 1000 copies/mL (quantitated using a genomicDNA curve). None of the MTB negative samples tested with the potentialcross-reactants was detected. All 80 MTB positive samples tested withpotential cross-reactants were detected.

TABLE 7 Microorganisms tested to determine analytical specificitySpecies Mycobacterium abscessus Mycobacterium austroafricanumMycobacterium avium Mycobacterium avium ssp. avium Mycobacterium aviumssp. Mycobacterium celatum Mycobacterium chelonae Mycobacterium chitaeMycobacterium fallax Mycobacterium flavescens Mycobacterium fortuitumMycobacterium gastri Mycobacterium gordonae Mycobacterium intracellulareMycobacterium kansasii Mycobacterium lentiflavum Mycobacterium marinumMycobacterium neoaurum Mycobacterium Mycobacterium phlei Mycobacteriumpneumoniae Mycobacterium pulveris Mycobacterium scrofulaceumMycobacterium shimoidei Mycobacterium simiae Mycobacterium smegmatisMycobacterium sphagni Mycobacterium terrae M. thermoresistibileMycobacterium tokaiense Mycobacterium ulcerans Mycobacterium vaccaeMycobacterium xenopi Acinetobacter baumannii Aeromonas hydrophilaBacillus cereus Bacillus subtilis Bordetella parapertussis Campylobacterjejuni Candida albicans Chromobacterium violaceum Chlamydia pneumoniaeChlamydia trachomatis Citrobacter freundii Corynebacterium diptheriaeCorynebacterium xerosis Cryptococcus neoformans CytomegalovirusEnterobacter aerogenes Enterobacter cloacae Enterococcus faecalisEnterococcus avium Escherichia coli Herpes simplex virus 1 Klebsiellapneumoniae Lactobacillus delbrueckii Legionella pneumophila Neisseriagonorrhoeae Neisseria meningitidis Porphyromonas gingivalis Proteusmirabilis Pseudomonas aeruginosa Salmonella choleraesuis Serratiamarcescens Staphylococcus aureus Staphylococcus epidermidisStaphylococcus haemolyticus Staphylococcus hominis Streptococcusagalactiae Streptococcus gordonae Streptococcus mitis Streptococcusmutans Streptococcus pneumoniae Streptococcus pyogenes Streptomycesgriseinus Varicella-zoster virus Veillonella parvula

Example 8 Analytical Sensitivity

A MTB panel, strain H37Rv at 40 cfu/mL was serially diluted in pooledMTB negative sputum to generate a sensitivity panel. Sixteen replicatesof each dilution were tested. A detection rate of 100% was observed atall dilutions 160 fold and lower. Results are shown in Table 8.

TABLE 8 Analytical sensitivity determined by testing serial dilutions ofa MTB panel. AM RealTime MTB Series dilution Ct cut off 42 Ct cut off 39from 40 cfu/mL Dil. Fold Hit Rate Hit Rate 1 0 16/16 16/16 2 2 16/1616/16 3 4 16/16 16/16 4 8 16/16 16/16 5 20 16/16 16/16 6 40 16/16 12/167 80 16/16 15/16 8 160 13/16 10/16 9 320 15/16  7/16 10 640  8/16  4/1611 1278  4/16  0/16 12 2564  3/16  0/16 13 5128  1/16  0/16

Example 9 Clinical Specificity

Culture-negative NALC samples (n=155), sputum (n=23) and BAL (n=28)samples (NALC samples were from MTB suspect population. Sputum and BALsamples were from patients with no TB symptoms) were tested to determineclinical specificity (see data summarized in table 10 below).Specificity for sputum and BAL samples was 100%. Specificity for NALCsamples was 98.7% with an overall specificity of 99%.

TABLE 9 Clinical specificity determined by testing TB negative samples.Specimen Specificity Tested Negative Positive type definition Numbersresults results Specificity NALC TB suspect 155 153 2 98.7%  Culturenegative Sputum No TB 23 23 0 100% symptom BAL No TB 28 28 0 100%symptom Total 206 204 2  99%

TABLE 10 TB Culture positive samples (including both smear positives andnegatives) were tested by MTB assay (AM) vs. another comparator assay(Comparator). SPECIMEN CULTURE FAM CY5 TUBE # TYPE RESULTS Ct MR Ct MRAM Comparator 39 SPUTUM TB 15.91 0.218 34.50 0.166 Detected high 38SPUTUM TB 16.76 0.225 34.55 0.176 Detected high 35 SPUTUM TB 19.88 0.23833.34 0.175 Detected high 23 SPUTUM TB 20.77 0.233 33.21 0.169 Detectedmed 30 BAL TB 21.79 0.226 33.18 0.177 Detected high 25 SPUTUM TB 22.280.222 33.54 0.171 Detected error 61 SPUTUM TB 22.84 0.227 33.96 0.179Detected med 45 SPUTUM TB 23.67 0.227 33.13 0.177 Detected high 44ASPIRATE TB 25.06 0.243 33.25 0.181 Detected high 34 SPUTUM TB 25.500.230 33.08 0.184 Detected med 63 SPUTUM TB 27.55 0.245 32.99 0.141Detected low 21 SPUTUM TB 27.61 0.229 33.54 0.187 Detected med 33ASPIRATE TB 27.63 0.247 33.31 0.182 Detected med 26 BAL TB 28.05 0.24833.70 0.187 Detected med 58 SPUTUM TB 28.26 0.215 33.88 0.177 Detectedmed 32 SPUTUM TB 29.26 0.225 36.49 0.177 Detected low 28 SPUTUM TB 29.430.241 33.15 0.197 Detected low 42 SPUTUM TB 29.82 0.228 35.19 0.184Detected med 60 SPUTUM TB 30.14 0.222 34.24 0.179 Detected low 59 SPUTUMTB 30.21 0.229 34.70 0.185 Detected low 29 SPUTUM TB 30.68 0.229 34.190.188 Detected low 57 SPUTUM TB 31.31 0.231 34.40 0.192 Detected low 24SPUTUM TB 31.70 0.239 35.37 0.191 Detected low 31 SPUTUM TB 32.73 0.189−1 0.008 Detected low 62 SPUTUM TB 33.12 0.237 34.52 0.185 Detected low27 BRONCHIA TB 35.00 0.232 34.55 0.185 Detected Not det WASH 55 LUNG TB36.67 0.212 34.76 0.176 Detected not tested* TISSUE 53 LUNG TB 37.710.277 35.94 0.177 Detected Not det TISSUE 51 SPUTUM TB 38.19 0.142 −10.003 Detected not tested* 46 SPUTUM TB 38.58 0.161 34.58 0.185 DetectedNot det 22 BAL TB −1 0.003 34.05 0.174 Not det Not det 36 SPUTUM TB −10.006 34.60 0.191 Not det Not det 37 SPUTUM TB −1 0.004 35.90 0.178 Notdet Not det 40 SPUTUM TB −1 0.004 34.42 0.178 Not det Not det 41 SPUTUMTB −1 0.002 34.79 0.182 Not det Not det 43 SPUTUM TB −1 0.004 34.970.165 Not det Not det 48 BAL TB −1 0.005 34.97 0.165 Not det Not det 49SPUTUM TB −1 0.001 34.58 0.168 Not det Not det 50 SPUTUM TB −1 0.00535.14 0.184 Not det Not det 54 SPUTUM TB −1 0.006 34.64 0.173 Not detNot det *“not tested” sample was because of not enough volume

The RealTime MTB showed better sensitivity at low end samples comparingto the comparator's assay.

Example 10 Analytical and Clinical Performance of MTB Assay

This Example describes the analytical performance of the real time MTBdetection assay.

Materials and Methods

The work flow for the real time MTB assay is described in FIG. 1.

Sample Inactivation

500 mL of Inactivation reagent (IR) was prepared by combining thefollowing components: 20 mL 10 M NaOH, 300 mL isopropanol, 0.9 mLTween-20, and 179.1 mL purified water. Once prepared the IR was stablefor up to one month at room temperature. If frozen, specimens(unprocessed specimens or processed NALCsediments) were thawed at 15° to30° C. Approximately three volumes of IR were added to each volume ofsample (the minimum allowable specimen volume is 0.3 mL). The samevolume ratio of sample:IR was maintained notwithstanding the type ofsample (unprocessed or NALC sediment). The mixture was vortexed twicefor 20 to 30 seconds each during the first hour of room temperatureincubation. The validated incubation time was one to 24 hours. Theinactivation process occurred under a biohood. Once completed, theinactivated samples were removed from under a biohood and then subjectedto sample preparation outside of the biohood. The inactivation processwas demonstrated to effectively reduce MTB viability at three differentlaboratories using cultured MTB added to NALC sediments of sputum, MTBpositive clinical NALC sediments, and MTB smear/culture positive sputumsamples (Qi C., et al., Effectiveness of the sample inactivationprocedure employed by the new Abbott RealTime assay for the detection ofMycobacterium tuberculosis, 24th European Congress of ClinicalMicrobiology and Infectious Diseases (ECCMID) 2014).

Sample Preparation

IR-treated specimens and the assay controls were loaded onto an m2000spinstrument where DNA was isolated using guanidinium thiocyanate-magneticmicroparticle technology to capture nucleic acids followed by washes toremove unbound components. An Internal Control (IC) was added at thestart of sample preparation. The bound nucleic acids were eluted andtransferred to a 96 deep-well plate. At the completion of samplepreparation, the m2000sp was used to create an amplification master mixconsisting of AmpliTaq Gold Polymerase, a magnesium chloride activationreagent, and oligonucleotide reagent containing primers, probes anddNTPs. The m2000sp was used to dispense 25 μl aliquots of the master mixfollowed by 25 μl aliquots of the extracted eluates to a 96-well opticalreaction plate. The plate was sealed manually and transferred to them2000rt for realtime PCR. As an alternative to the m2000sp, samplepreparation, mastermix preparation, and PCR plate set-up can beperformed manually.

Amplification and Detection

The m2000rt instrument was used for amplification and realtimefluorescence detection.

The detection of MTB complex members (Warren R M, et al., Int J TubercLung Dis 2006; 10:818-822) was achieved through the use of two sets ofprimers; one targeting the insertion element IS6110 (Thierry D, et al.,Nucleic Acids Res 1990; 18:188) and one the PAB gene (Anderson A B,Hansen E B Infect Immun 1989; 57:2481-2488). Signal for MTB complexdetection was generated with the use of fluorescent labelled probes. TheMTB dual target probes are each labeled with the fluorophore FAM at the5′ end and the Black Hole Quencher (BHQ1) at the 3′ end. Thus, MTBsignals from both IS6110 and PAB are detected in the same FAM channel.The amplification cycle at which FAM fluorescent signal is detected isproportional to the log of the MTB DNA concentration present in theoriginal sample. The probe for internal control (IC) is labelled withQuasar at the 5′ and Black Hole Quencher BHQ2 at the 3′ end to allow ICand target signals to be distinguishable in a single PCR well.

Assay Controls

A minimum of one replicate of the Negative Control and one replicate ofthe Positive Control were used to determine run validity. The NegativeControl consisted of TE buffer and preservatives. The Positive Controlconsisted of plasmid DNA containing both the IS6110 and PAB targetsequences diluted in TE buffer with 1.5 g/mL of poly dA:dT andpreservatives. The IC consisted of plasmid DNA containing a pumpkinhydroxypyruvate reductase (HPR) sequence insert diluted in TE bufferwith 1.5 g/mL of poly dA:dT and preservatives. IC was added at the startof sample preparation, serving as a control for sample preparationrecovery, sample inhibition, and amplification efficiency. The IC didnot control for the inactivation procedure. The IC threshold cycle (Ct)value difference between each sample and the run controls was used toassess the validity of each sample result.

Panels and Clinical Specimens

MTB Complex Subspecies:

Nineteen MTB complex subspecies DNA samples were obtained from theAmerican Type Culture Collection (ATCC, Manassas, Va.) and one (M.canettii) was provided kindly by Ibis Biosciences (Carlsbad, Calif.). Atotal of 20 MTB complex strains was tested including M. africanum 25420,M. africanum 35711, M. bovis 35735, M. bovis 19274, M. bovis BCG 35746,M. bovis BCG 35747D, M. canettii, M. caprae BAA-824D, M. microti 11152,M. microti 19422, M. pinnipedii BAA-688D, MTB 25177D-5 (H37Ra), MTB25618D-5 (H37Rv), MTB BAA-2236D, MTB BAA-2237D, MTB 27294D, MTBBAA-2234D, MTB 35822D, MTB 35838D, MTB BAA-2235D. Additionally, 46strains of the MTB subspecies including the three principal geneticgroups and nine genetic clusters were obtained from Dr. Barry Kreiswirthat the University of Medicine and Dentistry New Jersey (Newark, N.J.)(Mathema B, et al., Current Insights, Clinical Microbiology Reviews2006; 19:658-685). The DNA of the 20 MTB complex subspecies obtainedfrom ATCC and Ibis were directly tested using reported DNAconcentrations as determined by the PicoGreen® NanoDrop method. Theother 46 DNA concentrations were determined using PicoGreen® NanoDropmeasurements at Abbott Molecular with the exception of three sampleswhere such measurements could not be obtained due to low volume andimpurities. These three samples were diluted at a sample to water ratioof 1:600 and tested directly.

Limit of Detection [LOD]:

An MTB H37Rv panel targeted to 1×10⁵ colony forming units (cfu)/mL wasprepared by Zeptometrix (Buffalo, N.Y.). Three one mL aliquots of theZeptometrix panel were combined and centrifuged at 3,000×g for 15minutes to remove free MTB DNA in the supernatant. The cell pellet wasresuspended in three mL of TE buffer to maintain the concentration of1×10⁵ cfu/mL. The cells were then added to a pool of sputum, which washomogenized using bead-beating, to make the following MTB-containingdilution panels: 80 cfu/mL, 50 cfu/mL, 25 cfu/mL, 10 cfu/mL, 5 cfu/mL, 1cfu/mL, 0.50 cfu/mL, 0.10 cfu/mL, and 0.05 cfu/mL.

Analytical Specificity:

Analytical specificity panel members were collected as follows:Cytomegalovirus, Herpes Simplex virus 1, and Varicella-zoster virus wereobtained from Advanced Biotechnology Inc. (Columbia, Md.), 69mycobacterial and other microorganism species were obtained from ATCC,and eight bacterial isolates were cultured at Abbott Molecular.

Potentially Interfering Substances:

The following materials were obtained for this testing: blood, DNA fromhuman cells, gastric acid, hypertonic saline, physiologic saline,culture media, NALC pellet material, five anti-TB medications(Isoniazid, Rifampicin, Streptomycin, Pyrazinamide, Ethambutol), andbovine mucus.

Carryover:

Two samples were prepared: a high positive MTB sample containing 1×10⁷copies/mL of a plasmid containing the assay target sequences and anegative sample.

Reproducibility:

Two samples were prepared: a positive sample containing an MTBconcentration of ˜three times the claimed assay LOD and a negativesample.

Clinical Specimens:

198 sputum specimens were collected by Discovery Life Sciences (LosOsos, Calif.) from TB suspect patients in Russia, South Africa, Uganda,and Vietnam. 150 sputum specimens from Vietnam were obtained from thespecimen bank operated by the Foundation for Innovative New Diagnostics(FIND) (Geneva, Switzerland). 234 NALC specimens were obtained fromNorthwestern University Memorial Hospital (Chicago, Ill.). All patientspecimens were collected under ethical guidelines. The HIV status of thepatients was not determined. For all specimens smear (when available)and culture testing was performed near the collection site, while AbbottRealTime MTB assay testing was performed at Abbott Molecular.

Results MTB Complex Subspecies Detection

This study was conducted to determine whether the specific primers andprobes used in MTB assays would detect the following eight MTB complexsub-species: M. africanum, M. bovis, M. bovis BCG, M. canettii, M.caprae, M. microti, M. pinnipedii, and M. tuberculosis. Two sets ofpurified MTB complex DNAs were tested. The first set of 20 purified DNAscontained representatives of the previously mentioned MTB sub-species.Each purified DNA was tested at two concentrations (100 and 10genomes/reaction) with four replicates being tested per concentration.At the 100 MTB genomes per reaction level, all four replicates of eachof the 20 MTB strains were detected. At the 10 MTB genomes per reactionlevel, all four replicates of 17 of the strains were detected. For threestrains (two M. bovis and one M. bovis BCG) two of the four replicateswere detected (FIG. 4). The second set of 46 MTB strains from the MTBsub-species were tested at two concentrations: 100 genomes/reaction and25 genomes/reaction. Four replicates of each DNA were tested at eachconcentration. All the tested replicates were positive at bothconcentrations (FIG. 2).

Limit of Detection (LOD)

A nine-level dilution series was made from MTB strain H37Rv cellsdiluted in a glass bead homogenized sputum pool. The panel members inthe dilution series were targeted to the following concentrations: 80cfu/mL, 50 cfu/mL, 25 cfu/mL, 10 cfu/mL, 5 cfu/mL, 1 cfu/mL, 0.50cfu/mL, 0.10 cfu/mL, and 0.05 cfu/mL. Twenty replicates of each panelmember were tested across four runs using the Abbott RealTime MTB assay.The study was conducted using one lot of MTB assay and control reagents.The significance level for this study was 0.05. The detection rate wascalculated for each target concentration (Table 11). A Probit regressionmodel was fitted, based on the target concentrations and the detectionrate using PROC PROBIT in SAS, with the target concentration (X) as theindependent variable and the detection rate P (Y=1) as the responsevariable. The Probit analysis of the data determined that theconcentration of MTB detected with 95% probability was 2.45 cfu/mL (95%CI 1.44-6.10 cfu/mL). The claimed analytical sensitivity of the AbbottRealTime MTB assay is 17 cfu/mL in pooled homogenized sputum using theMTB H37Rv strain.

Analytical Specificity

Each of the 80 potential cross-reactants was tested in both an MTBpositive sample and an MTB negative sample. Nucleic acid from eachpotentially cross-reacting mycobacterium, virus, or other microorganismat a targeted concentration of 1×10⁵ to 1×10⁷ copies or genomes per mLwas added to the MTB positive samples (containing 1,000 MTB genomes/mL)and the MTB negative samples. Cultured microorganisms at a targetconcentration of 1×10⁶ cfu/mL were added to the MTB positive samples andthe MTB negative samples. The assay results for all 80 negative sampleswere reported as “MTB Not Detected”. The assay results for all 80MTB-containing samples were reported as “MTB Detected” (Table 7).

Potentially Interfering Substances

The potential for interference in the test results was assessed withsubstances that may be present in the respiratory system. MTB negativeand MTB positive (500 copies/mL) samples were tested in the absence orthe presence of each potentially interfering substance with elevatedlevels of bovine mucus, blood, DNA from human cells, gastric acid,hypertonic saline, physiological saline, culture media, NALC pelletmaterial and five anti-TB medications (Isoniazid, Rifampicin,Streptomycin, Pyrazinamide, Ethambutol) (Table 12). The results showedno interference in the performance of the MTB assay in the presence ofhigh levels of blood, DNA from human cells, gastric acid, hypertonicsaline, physiological saline, culture media, NALC pellet material andfive anti-TB medications (Isoniazid, Rifampicin, Streptomycin,Pyrazinamide, Ethambutol). Interference of the Abbott RealTime MTB assaywas observed in the presence of bovine mucus at 8.3% (all fivereplicates were false negative or inhibited) and 5.0% (one of fivereplicates was false negative). No interference was found at bovinemucus concentrations of 2.5% or less.

Carryover

To evaluate the potential of carryover from high positive MTB samples tonegative samples when using the Abbott RealTime MTB assay, five m2000system runs each consisting of 96 samples (Positive Control, NegativeControl, 46 high positive samples at 1×10⁷ copies/mL and 46 negativesamples) in which the high positive samples were interspersed amongnegative samples. The MTB concentration in the high positive sample of1×10⁷ copies/mL resulted in a Ct value that was earlier than 95% or moreof the results obtained from specimens of the MTB positive populationtested with the MTB assay. The assay did not exhibit any carryover fromhigh positive samples to the 230 negative samples in the five runs. A 96sample run was completed in less than 8 hours.

Reproducibility

A reproducibility test was performed to evaluate the Abbott RealTime MTBassay repeatability in the m2000 system and the compatibility betweenthe Abbott m2000sp instrument and the manual sample preparation method.The study was performed with a positive panel at three times the claimedLOD level and a negative panel. The study was conducted by fouroperators using two lots of MTB amplification reagents: two operatorsperforming runs using an Abbott m2000sp instrument and two operatorsperforming runs using manual sample preparation. For each samplepreparation method, the two operators each used one unique lot of AbbottRealTime MTB amplification reagents and tested each panel member inreplicates of eight, once per day, for five days, for a total of 40replicates per panel member (80 total replicates per panel member permethod; 160 total tested with m2000sp instrument sample preparation and160 total tested with manual sample preparation). The overall agreementwith expected results was 100% (159/159, one sample was invalid becauseof an instrument error) with a lower 95% CI of 98.1% for samplesprepared with the Abbott m2000sp instrument or with manual samplepreparation. The MTB assay is compatible with both the Abbott m2000spinstrument and the Abbott manual sample preparation method.

Clinical Sensitivity and Specificity

One sputum or one NALC sediment was tested from each of 582 TB suspectpatients. Samples were collected from Russia, South Africa, Uganda, theUnited States, and Vietnam. Each specimen was split to allow testing ofMTB on one aliquot and smear and culture on the second aliquot. Thetesting samples were blinded and final result decoding was performed byAM statistical group. For MTB testing, two specimens generated aninvalid IC result, and an additional four specimen results gave m2000error codes. The frequency of clinical specimens with invalid resultsmeasured by inhibition was 0.3% (2/582), while the invalid rateincluding both inhibition and instrument errors was 1.0% (6/582). Fiveculture negative specimens that were positive by both the MTB assaydescribed herein and a commercially available MTB NAAT were excludedfrom the analysis. A total of 571 valid samples were included for dataanalysis. The overall MTB sensitivity versus culture was 93% (198/212).The assay sensitivity was 99% (147/149) in smear positive, culturepositive specimens, and 81% (51/63) in smear negative, culture positivesamples. The specificity was 97% (348/359) (Table 13). 76 of the MTBnegative samples contained Non-Tuberculous Mycobacteria (NTM). Of these,38 were MAC (M. avium complex), seven were M. gordonae, five were M.kansasii, five were M. chelonae/abcessus, three were M. xenopi, and 18contained other mycobacterial species. With the MTB assay describedherein, all of the NTM sample results were “MTB Not Detected” with theexception of two samples that produced “MTB Detected” results with lateCN (>38) values as compared to the assay cutoff of 40. The specificityvalue of 97% resulted from testing the NTM population is similar to thespecificity observed when testing the non-NTM population. Furthermore500 non-TB suspect patient sputum samples collected from within the U.S.population showed 100% TB negative test results.

TABLE 11 Limit of Detection Target Concentration Number Number DetectionPercent (cfu/mL) Tested Detected Rate Detected 80 20 20 1.00 100 50 2020 1.00 100 25 20 20 1.00 100 10 20 20 1.00 100 5 20 20 1.00 100 1 20 180.90 90 0.50 20 7 0.35 35 0.10 20 2 0.10 10 0.05 20 1 0.05 5

A probit analysis of the Abbott RealTime MTB data determined that theconcentration of MTB detected with 95% probability was 2.45 cfu/mL at CNcutoff 40 (95% Confidence Interval of 1.44-6.10 cfu/mL).

TABLE 12 Potential interfering substances and theirconcentrations/percentages tested to determine susceptibility tointerfering substances Potentially Interfering Specimen Substance SourceConcentration/Percentage Mucus Sputum Mucin 5% (w/v) Blood Sputum or BAL5% (v/v) DNA from human cells Sputum, BAL, 10⁶ cells/mL NALC Sedimentsof Sputum/BAL Gastric acid Sputum/BAL pH 3 to 4 HCl in water,neutralized to pH 6 to 8 with sodium bicarbonate Hypertonic saline usedSputum NaCl (5% w/v) to induce sputum Physiologic saline used BAL NaCl(0.9% w/v) to collect BAL Culture media MTB culture 100% Material usedto NALC pellets 0.067M phosphate, resuspend NALC pellets pH 6.8Isoniazid Sputum or BAL 90 mg/mL (Anti-TB medication)Rifampicin/Rifampin Sputum or BAL 120 ug/mL (Anti-TB medication)Streptomycin Sputum or BAL 400 ug/mL (Anti-TB medication) PyrazinamideSputum or BAL 500 ug/mL (Anti-TB medication) Ethambutol Sputum or BAL 60ug/mL (Anti-TB medication)

TABLE 13 Sensitivity and specificity obtained when testing clinicalspecimens Culture/Smear results Sensitivity Specificity C+/S+ C+/S− C+C− RealTime MTB 99% 81% 93% 97% (147/149) (51/63) (198/212) (348/359)

Example 11 Inactivation Reagents

This example describes inactivation reagents for use in MTB detectionassays. The assay is a NAAT for the detection of MTB complex DNA inrespiratory specimens (sputum, bronchial alveolar lavage (BAL) andN-acetyl-L-cysteine (NALC) sediments of sputum and bronchial alveolarlavarge (BAL). A sample inactivation reagent and procedure weredeveloped to liquefy viscous samples and to reduce MTB viability toallow for safe testing of samples outside biosafety cabinets. The studywas to assess the effectiveness of the sample inactivation procedure andto determine the stability of the Inactivation Reagent (IR).

For the viscosity reduction study, 150 sputum samples were mixed with IR(0.6% sodium hydroxide [w/v], 60% isopropanol [v/v], and 1.8% Tween-20[v/v]) at a ratio of 1:2 or 1:3. The mixtures were vortexed vigorouslyand incubated at room temperature. The mixture was vortexed again after20 to 30 minutes of incubation. Reduction of viscosity was assessed byvisual examined after 30 minutes, 60 minutes, and 24 hours ofincubation.

For the inactivation study, two MTB clinical isolates and MTB ATCC 27294isolate were used to prepare mock MTB positive respiratory samples bymixing one mL of MTB cell suspension in the concentrations of 1×10⁶,1×10⁷, or 1×10⁸ cfu/mL with four mL of pooled MTB negative NALC treatedrespiratory sample. Each mock MTB NALC sample was then mixed with IR atratios of 1:2 or 1:3. A mock sample treated with sterile PBS buffer at asample to PBS ratio of 1:2 was used as the positive control. Negativecontrols were prepared by adding sterile PBS to the pooled MTB negativeNALC sample at a ratio of PBS to NALC of 1:2. All samples/controls werevortexed vigorously and incubated for 60 minutes at room temperature.Vortexing was repeated 30 minutes into the incubation. At the end of theincubation, the IR treated samples were transferred into new 50 mLtubes, vortexed and centrifuged for 15 minutes at 3000×g. The sedimentwas re-suspended in 10 mL sterile PBS and centrifuged for an additional15 minutes at 3000×g. Pellets were each re-suspended in 10 mL sterilePBS. One mL of the suspension was used to inoculate a MycobacterialGrowth Indicator Tube (MGIT). The final MTB added to each MGIT cultureranged from 1-2×10⁴ to 1-2×10⁶ cfu. In addition, a total of 51 MTBpositive clinical NALC sediments of sputum, 20 from NorthwesternMemorial hospital and 31 from Lancet Laboratories, were tested forgrowth after the IR treatment at a sample to IR ratio of 1:3 with thesame procedure. Ten of the 20 samples from Northwestern MemorialHospital were treated at a sample to IR ratio of 1:2. The remaining 41samples were treated with a sample to IR ration of 1:3. Culture wasperformed with BACTEC MGIT 960 system (Becton Dickinson, Sparks, Md.)for 42 days. Positive growth was identified with Gen-Probe Accuprobe®system (Gen-Probe Inc, San Diego, Calif.). Initial studies todemonstrate the inactivation efficiency of direct respiratory samples(MTB smear and culture positive sputum samples) were also performed incombination with an IR stability study as described in the followingparagraph.

To determine the optimal storage condition for IR, three aliquots of IRwere stored for 39 days at storage conditions of 15-30° C. and 33-37° C.in glass or polypropylene bottles. Each aliquot of IR at each storagecondition was examined for changes in appearance and volume and testedfor MTB inactivation efficacy after 39 days of storage with 12 MTB smearand culture positive sputum samples obtained from SAGE Bio Networks(Dhaka, Bangladesh) and Foundation for Innovative New Diagnostics (FIND)MTB specimen bank using a 1:3 sample to IR ratio. An MTB strain H37Rvcell panel obtained from Zeptometrix Corporation (Buffalo, N.Y.) wasused as the Positive Control.

The viscosity reduction study showed that 60 minutes of incubation wassufficient to reduce the viscosity of the samples. For the inactivationstudy, none of the mock MTB samples prepared with the three MTB isolatesat 1×10⁸, 1×10⁷, and 1×10⁶ cfu/mL showed MTB growth after being treatedwith IR at a sample to IR ratio of 1:3. One IR-treated sample, preparedwith 1×10⁷ cfu/mL MTB and treated with IR at a sample to IR ratio of1:2, showed growth after 27 days of incubation, although two repeats atthe same bacterial concentration tested negative for growth. None of the20 MTB positive NALC sputum sediments showed MTB growth following thetreatment with IR at a sample to IR ratio of 1:2 or 1:3. Further, 31clinical NALC sputum sediments that had previously tested positive forMTB by culture were tested negative for MTB growth after receiving IRtreatment at 1:3 sample to IR ratio.

Changes in appearance after storage were not observed after 39 days. Avolume loss of 0 to 6% was observed after 39 days of storage. Thehighest volume loss of 6% was observed when IR was stored inpolypropylene containers at 33-37° C. However, the efficiency of the IRsolution to inactivate MTB was not affected after storage. The 12 MTBpositive sputum samples showed no growth after being treated with the IRstored under the various conditions described above.

It was noted that some MTB in clinical samples survived the recommendedCepheid GeneXpert MTB/RIF sample inactivation process (15 minuteincubation period and a 1:2 sample to Sample Reagent ratio) (Banada, P.P., et al., 2010. J. Clin. Microbiol. 48:3551-3557). The authorssuggested complete MTB inactivation may require a longer incubationtime. Experimental data generated by the study described hereindemonstrated that sample inactivation performed for 60 minutes using therecommended vortexing steps was sufficient for complete MTBinactivation.

When a 1:2 sample to IR ratio was used, one replicate of a 1×10⁷ MTBcfu/mL culture (2×10⁵ cfu/mL in the MGIT culture) showed growth after 27days of incubation of the MGIT culture. A previous study showed thatMGIT cultures containing 10 cfu/mL of MTB became positive after 16 daysof incubation, the result suggested that a very low number MTB survivedthe inactivation process when a 1:2 sample to IR ratio was used(Tortoli, E., P. et al., J. Clin. Microbiol. 37(11):3578-3582; Wallis,et al., 1999. Antimicrobial Agents and Chemotherapy, 43:2600-2606). Toachieve the optimal inactivation efficiency, the sample to IR ratio of1:3 was used for the rest of the inactivation experiments.

In conclusion, the IR evaluated in this study was able to liquefy sputumsamples and to achieve effective inactivation of MTB in clinicalspecimens when treated with IR at a sample to IR ratio of 1:3 for 60minutes. This inactivation procedure enables these samples to be safelyhandled outside of a biosafety cabinet after the proper inactivationprocedure.

We claim:
 1. A composition, comprising: at least one primer pairselected from the group consisting of SEQ ID NOs: 1 and 2, SEQ ID NOs: 3and 4, and SEQ ID NOs: 7 and
 8. 2. The composition of claim 1, whereinsaid composition comprises SEQ ID NOs: 1-4 and 7-8.
 3. The compositionof claim 1, wherein said composition further comprises at least oneprobe selected from the group consisting of SEQ ID NOs: 5, 6, and
 9. 4.The composition of claim 1, wherein said primer pairs are SEQ ID NOs: 1and 2 and SEQ ID NOs: 3 and
 4. 5. The composition of claim 1, whereinone of more of the recited SEQ ID NOs comprises a label.
 6. Thecomposition of claim 5, wherein said label comprises a fluorophore. 7.The composition of claim 5, wherein said label comprises afluorophore/quencher pair.
 8. The composition of claim 1, wherein saidcomposition further comprises one or more nucleic acid sequencesselected from the group consisting of SEQ ID NOs: 10-36.
 9. Thecomposition of claim 1, wherein said composition is a reaction mixture.10. The composition of claim 9, wherein said reaction mixture comprisesa sample.
 11. The composition of claim 9, wherein said sample comprisesa sample comprising a mycobacterium tuberculosis (MTB) target nucleicacid.
 12. A kit, comprising: a) the composition of claim 1; and b) atleast one reagent for performing a nucleic acid amplification reaction.13. The kit of claim 12, wherein said reagent is selected from a nucleicacid polymerase; a plurality of dNTPS, a buffer, and an inactivationreagent.
 14. A method of identifying an MTB nucleic acid in a biologicalsample, comprising: a) contacting a biological sample from a subjectwith a nucleic acid primer or probe of SEQ ID NOs:1-9, and b) detectingthe binding of said nucleic acid primer or probe to said MTB nucleicacid.
 15. The method of claim 14, further comprising the step of c)determining the presence of MTB in said sample when said binding isdetected.
 16. The method of claim 14, wherein said detecting comprisesreal time PCR.
 17. The method of claim 14, wherein said method furthercomprises the step of inactivating said MTB in said sample using aninactivation reagent prior to said contacting.
 18. The method of claim17, wherein said inactivation reagent comprises water, a detergent, analcohol, and NaOH.
 19. The method of claim 17, wherein said inactivationreagent comprise isopropanol, sodium hydroxide, TWEEN-20, and water. 20.The method of claim 14, wherein said sample is sputum, bronchoalveolarlavage [BAL], or N-acetyl-L-cysteine [NALC] sediments of sputum.